>>> import awkward as ak
>>> a = ak.from_iter([[None, 1], None, [1, 2]])
>>> ak.is_none(a, axis=0)
<Array [False, True, False] type='3 * bool'>
>>> ak.is_none(a, axis=1)
<Array [[True, False], None, [False, False]] type='3 * option[var * bool]'>
>>> tt = ak.Array(a.layout.typetracer.forget_length())
>>> ak.is_none(tt, axis=0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 28, in is_none
    return _impl(array, axis, highlevel, behavior)
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 82, in _impl
    out = layout.recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/content.py", line 1588, in recursively_apply
    return self._recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/indexedoptionarray.py", line 1626, in _recursively_apply
    result = action(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 72, in getfunction_outer
    return layout.recursively_apply(getfunction_inner, behavior)
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/content.py", line 1588, in recursively_apply
    return self._recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/indexedoptionarray.py", line 1626, in _recursively_apply
    result = action(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 47, in getfunction_inner
    index = nplike.index_nplike.where(tag, 0, nplike.asarray(layout.index))
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/_typetracer.py", line 789, in where
    raise ak._errors.wrap_error(NotImplementedError)
NotImplementedError: 

See if this has been reported at https://github.com/scikit-hep/awkward-1.0/issues
>>> ak.is_none(tt, axis=1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 28, in is_none
    return _impl(array, axis, highlevel, behavior)
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 82, in _impl
    out = layout.recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/content.py", line 1588, in recursively_apply
    return self._recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/indexedoptionarray.py", line 1640, in _recursively_apply
    return continuation()
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/indexedoptionarray.py", line 1602, in continuation
    content._recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/listoffsetarray.py", line 2033, in _recursively_apply
    return continuation()
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/listoffsetarray.py", line 1995, in continuation
    content._recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/indexedoptionarray.py", line 1626, in _recursively_apply
    result = action(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 72, in getfunction_outer
    return layout.recursively_apply(getfunction_inner, behavior)
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/content.py", line 1588, in recursively_apply
    return self._recursively_apply(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/contents/indexedoptionarray.py", line 1626, in _recursively_apply
    result = action(
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/operations/ak_is_none.py", line 47, in getfunction_inner
    index = nplike.index_nplike.where(tag, 0, nplike.asarray(layout.index))
  File "/Users/ddavis/.pyenv/versions/dev/lib/python3.10/site-packages/awkward/_typetracer.py", line 789, in where
    raise ak._errors.wrap_error(NotImplementedError)
NotImplementedError: 

See if this has been reported at https://github.com/scikit-hep/awkward-1.0/issues