Failed to extract metadata: Indexing elements must be in increasing order

Hello,

I've made some nwb files and am trying to upload them to DANDI using `dandi upload`. I have three of them. Two upload just fine. The other one hits this error trace:

```
2026-05-28T16:06:11+0100 [WARNING ] dandi 923713:127939540670144 Failed to extract NWB metadata from /home/nolanlab/fromgit/nolanlab_nwb/001854/sub-M22/sub-M22_ses-D34OF2_ecephys+behavior.nwb: TypeError: Indexing elements must be in increasing order
2026-05-28T16:06:11+0100 [ERROR ] dandi 923713:127939540670144 Error uploading /home/nolanlab/fromgit/nolanlab_nwb/001854/sub-M22/sub-M22_ses-D34OF2_ecephys+behavior.nwb:
Traceback (most recent call last):
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/upload.py", line 392, in process_path
metadata = dfile.get_metadata(
~~~~~~~~~~~~~~~~~~^
digest=file_etag, ignore_errors=allow_any_path
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
).model_dump(mode="json", exclude_none=True)
^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/files/bases.py", line 494, in get_metadata
metadata = nwb2asset(self.filepath, digest=digest)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/metadata/nwb.py", line 149, in nwb2asset
metadata = get_metadata(nwb_path)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/fscacher/cache.py", line 164, in fingerprinter
ret = fingerprinted(*args, **kwargs_)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/joblib/memory.py", line 607, in __call__
return self._cached_call(args, kwargs, shelving=False)[0]
~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/joblib/memory.py", line 562, in _cached_call
return self._call(call_id, args, kwargs, shelving)
~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/joblib/memory.py", line 832, in _call
output = self.func(*args, **kwargs)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/fscacher/cache.py", line 100, in fingerprinted
return f(path, *args, **kwargs)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/metadata/nwb.py", line 106, in get_metadata
meta.update(_get_pynwb_metadata(r))
~~~~~~~~~~~~~~~~~~~^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/pynwb_utils.py", line 279, in _get_pynwb_metadata
session_duration = _get_session_duration(nwb)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/pynwb_utils.py", line 350, in _get_session_duration
start = float(np.min(np.r_[st_data[0], st_data[idxs[:-1]]]))
~~~~~~~^^^^^^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/hdmf/container.py", line 1002, in __getitem__
return self.get(args)
~~~~~~~~^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/hdmf/common/table.py", line 61, in get
return super().get(key)
~~~~~~~~~~~^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/hdmf/container.py", line 1010, in get
return self.data[args]
~~~~~~~~~^^^^^^
File "h5py/_objects.pyx", line 56, in h5py._objects.with_phil.wrapper
File "h5py/_objects.pyx", line 57, in h5py._objects.with_phil.wrapper
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/h5py/_hl/dataset.py", line 893, in __getitem__
selection = sel.select(self.shape, args, dataset=self)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/h5py/_hl/selections.py", line 82, in select
return selector.make_selection(args)
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "h5py/_selector.pyx", line 282, in h5py._selector.Selector.make_selection
File "h5py/_selector.pyx", line 215, in h5py._selector.Selector.apply_args
TypeError: Indexing elements must be in increasing order

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/upload.py", line 396, in process_path
raise UploadError("failed to extract metadata: %s" % str(e))
dandi.exceptions.UploadError: failed to extract metadata: Indexing elements must be in increasing order
2026-05-28T16:06:11+0100 [DEBUG ] urllib3.connectionpool 923713:127941258118976 Starting new HTTPS connection (1): rig.mit.edu:443
2026-05-28T16:06:16+0100 [DEBUG ] dandi 923713:127941258118976 Caught exception failed to extract metadata: Indexing elements must be in increasing order
Traceback (most recent call last):
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/upload.py", line 392, in process_path
metadata = dfile.get_metadata(
~~~~~~~~~~~~~~~~~~^
digest=file_etag, ignore_errors=allow_any_path
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
).model_dump(mode="json", exclude_none=True)
^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/files/bases.py", line 494, in get_metadata
metadata = nwb2asset(self.filepath, digest=digest)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/metadata/nwb.py", line 149, in nwb2asset
metadata = get_metadata(nwb_path)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/fscacher/cache.py", line 164, in fingerprinter
ret = fingerprinted(*args, **kwargs_)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/joblib/memory.py", line 607, in __call__
return self._cached_call(args, kwargs, shelving=False)[0]
~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/joblib/memory.py", line 562, in _cached_call
return self._call(call_id, args, kwargs, shelving)
~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/joblib/memory.py", line 832, in _call
output = self.func(*args, **kwargs)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/fscacher/cache.py", line 100, in fingerprinted
return f(path, *args, **kwargs)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/metadata/nwb.py", line 106, in get_metadata
meta.update(_get_pynwb_metadata(r))
~~~~~~~~~~~~~~~~~~~^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/pynwb_utils.py", line 279, in _get_pynwb_metadata
session_duration = _get_session_duration(nwb)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/pynwb_utils.py", line 350, in _get_session_duration
start = float(np.min(np.r_[st_data[0], st_data[idxs[:-1]]]))
~~~~~~~^^^^^^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/hdmf/container.py", line 1002, in __getitem__
return self.get(args)
~~~~~~~~^^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/hdmf/common/table.py", line 61, in get
return super().get(key)
~~~~~~~~~~~^^^^^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/hdmf/container.py", line 1010, in get
return self.data[args]
~~~~~~~~~^^^^^^
File "h5py/_objects.pyx", line 56, in h5py._objects.with_phil.wrapper
File "h5py/_objects.pyx", line 57, in h5py._objects.with_phil.wrapper
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/h5py/_hl/dataset.py", line 893, in __getitem__
selection = sel.select(self.shape, args, dataset=self)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/h5py/_hl/selections.py", line 82, in select
return selector.make_selection(args)
~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
File "h5py/_selector.pyx", line 282, in h5py._selector.Selector.make_selection
File "h5py/_selector.pyx", line 215, in h5py._selector.Selector.apply_args
TypeError: Indexing elements must be in increasing order

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/cli/base.py", line 126, in wrapper
return f(*args, **kwargs)
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/cli/cmd_upload.py", line 113, in upload
upload_(
~~~~~~~^
paths,
^^^^^^
...<9 lines>...
validation_log_path=companion,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/upload.py", line 505, in upload
raise upload_err
File "/home/nolanlab/fromgit/nolanlab_nwb/.venv/lib/python3.13/site-packages/dandi/upload.py", line 396, in process_path
raise UploadError("failed to extract metadata: %s" % str(e))
dandi.exceptions.UploadError: failed to extract metadata: Indexing elements must be in increasing order
```

I don't know what this means, or how to proceed.

Strange things:
- `dandi validate` runs fine.
- the metadata is generated in the same way for all nwb files, so I don' t understand why only one of them would fail.
- When I open the nwb file using pynwb, it looks fine and all the metadata looks reasonable.

Any advice very welcome!