Errors using with concurrent.futures

Hi. I use concurrent.futures to handle multi-threading/multi-processing. I can get a basic example to work fine with numpy_quaddtype. But when I try my full normal test (that works with standard numpy) I get:

  File "/Users/kaplan/miniforge3/envs/pintdev_arm/lib/python3.14/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/kaplan/miniforge3/envs/pintdev_arm/lib/python3.14/concurrent/futures/process.py", line 242, in _process_worker
    call_item = call_queue.get(block=True)
  File "/Users/kaplan/miniforge3/envs/pintdev_arm/lib/python3.14/multiprocessing/queues.py", line 120, in get
    return _ForkingPickler.loads(res)
           ~~~~~~~~~~~~~~~~~~~~~^^^^^
RuntimeError: Using legacy SETITEM with NULL array object is only supported for basic NumPy DTypes.

I don't know if I am not triggering this function with my basic example or what. I understand that it may be using pickling to pass between the different processes, but don't know if this can be fixed through a change on my end or if this has to be done here or in multiprocessing. Any ideas?

(sorry about the poorly formatted question)

Start by comparing the working basic example with the full test using concurrent.futures, then trace the failure through multiprocessing/process.py, concurrent/futures/process.py, and multiprocessing/queues.py. Confirm whether the numpy_quaddtype value fails during pickling or unpickling, and document a minimal reproducible case plus the component that needs the fix.