count_nested changes types after query

[delucchi-cmu]

Bug report

I would expect the values in the count_nested returned frame to always take on integer values, and to have 0 if some value is not present.

Behavior mostly matches, but after the query in the below example, the counts are now floats and NaN.

Environment Information

--------      SYSTEM INFO      --------
python        : 3.12.11
python-bits   : 64
OS            : Linux
OS-release    : 5.14.0-570.58.1.el9_6.x86_64
Version       : #1 SMP PREEMPT_DYNAMIC Fri Oct 31 13:55:05 UTC 2025
machine       : x86_64
processor     : 
byteorder     : little
LC_ALL        : 
LANG          : 
--------   INSTALLED VERSIONS   --------
lsdb          : 0.8.2
hats          : 0.8.2
nested-pandas : 0.6.8
pandas        : 2.3.1
numpy         : 2.4.2
dask          : 2025.7.0
pyarrow       : 17.0.0
fsspec        : 2025.7.0

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Please check the following:

• I have described the situation in which the bug arose, including what code was executed, and any applicable data others will need to reproduce the problem.
• I have included information about my environment, including the version of this package (e.g. nested_pandas.__version__)
• I have included available evidence of the unexpected behavior (including error messages, screenshots, and/or plots) as well as a description of what I expected instead.
• If I have a solution in mind, I have provided an explanation and/or pseudocode and/or task list.

[delucchi-cmu]

I'm able to work around for now with

count_nested(new_data, f"objectForcedSource", by="band", join=False).fillna(0).astype(int)