Threading Lock issue with to_netcdf and Dask arrays

I have multiple netCDF files that I process and write to a single output file.

from pathlib import Path

import xarray as xr

DS = xr.open_mfdataset(Path('L3_data/').glob('**/*.nc'),
                       combine='nested',
                       concat_dim='time',
                       decode_times=False,
                       chunks={'time': 200})

DS.to_netcdf('test.nc')

I was not able to reproduce the issue with a simple example, here are the files : L3_data.zip. The issue does not appear systematically but sometimes, .to_netcdf blocks indefinitely. When interrupted manually, the trace is the following:

Traceback (most recent call last):
  File "test_xarray.py", line 11, in <module>
    DS.to_netcdf('test.nc')
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/xarray/core/dataset.py", line 1568, in to_netcdf
    invalid_netcdf=invalid_netcdf,
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/xarray/backends/api.py", line 1090, in to_netcdf
    writes = writer.sync(compute=compute)
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/xarray/backends/common.py", line 204, in sync
    regions=self.regions,
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/dask/array/core.py", line 945, in store
    result.compute(**kwargs)
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/dask/base.py", line 167, in compute
    (result,) = compute(self, traverse=False, **kwargs)
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/dask/base.py", line 452, in compute
    results = schedule(dsk, keys, **kwargs)
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/dask/threaded.py", line 84, in get
    **kwargs
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/dask/local.py", line 475, in get_async
    key, res_info, failed = queue_get(queue)
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/site-packages/dask/local.py", line 133, in queue_get
    return q.get()
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/queue.py", line 170, in get
    self.not_empty.wait()
  File "/Users/bilelomrani/opt/miniconda3/envs/s5p/lib/python3.7/threading.py", line 296, in wait
    waiter.acquire()
KeyboardInterrupt

Environment:

I'm on Mac OS 10.15.6

Start by reproducing the hang with the attached L3_data.zip and the shown DS.to_netcdf call. Trace the writer.sync path through xarray/core/dataset.py, xarray/backends/api.py, and xarray/backends/common.py, alongside the Dask threaded scheduler shown in the traceback. Done means the operation completes reliably and the regression is covered by a reproducible test.