[Bug]: file create date is not appendable if the file is generated by pynwb

[laurelrr]

What happened?

I recently created an nwb file using the tye-lab-to-nwb neurotensin package on github (a pynwb package). Later, I wanted to change some of the general fields and loaded the file into matlab:

 > nwb = nwbRead('H07_DiscS.nwb');
 > nwb.general_subject.age = 'P109D';
 > nwbExport(nwb,'H07_DiscS.nwb')

but this gave me an error:

Warning: Attempted to change size of continuous dataset `/file_create_date`.  Skipping.
> In io.writeDataset (line 26)
In types.core/NWBFile/export (line 849)
In NwbFile/export (line 66)
In nwbExport (line 42)  

I expected this to write out an updated NWB file. However, the export function tries to add a second date into the 'file_create_date' field:

>> nwb.file_create_date
ans =
  1×2 cell array
    {[2023-10-10T14:38:34.356656-07:00]}    {[2023-10-20T14:54:46.150750-07:00]}

I am working on Windows 11, using Matlab 9.14.0.2286388 (R2023a) Update 3, with matnwb version 2.6.0. installed.
The original file was 'auto-generated using neuroconv'.

Steps to Reproduce

(Using python, inside tye-lab-to-nwb folder)
> conda activate tyenwbevn39
> python src/tye_lab_to_nwb/neurotensin_valence/neurotensin_valence_convert_all_sessions.py

(In matlab)
 > nwb = nwbRead('H07_DiscS.nwb');
 > nwb.general_subject.age = 'P109D';
 > nwbExport(nwb,'H07_DiscS.nwb')

Error Message

Warning: Attempted to change size of continuous dataset `/file_create_date`.  Skipping.
> In io.writeDataset (line 26)
In types.core/NWBFile/export (line 849)
In NwbFile/export (line 66)
In nwbExport (line 42)

Operating System

Windows

Matlab Version

9.14.0.2286388 (R2023a) Update 3

Code of Conduct

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[lawrence-mbf]

This warning message is actually somewhat expected and, indeed, is intended for compatibility with pynwb already since the behavior for editing files in MatNWB will differ slightly from pynwb regarding /file_create_date.