[BUG] arc i edit deletes complete Investigation when editing an Investigation with a Comment field

[omaus]

Describe the bug
When using arc i edit on an Investigation that already has a Comment field (e.g. Comment[myComment] with an arbitrary value), the ArcCommander overwrites the current Investigation with a completely empty one. It doesn't matter what you edit with arc i edit, except for deleting the Comment field or altering it.

To Reproduce
Steps to reproduce the behavior:

1. Create an ARC with an Investigation
2. With the ArcCommander:
   a. Use arc i edit
   b. Write Comment[myComment]: test into a new line
   c. Save and close the text editor prompt
3. With MS Excel (or any program that can be used to work with Xlsx files):
   a. Open the Investigation file
   b. Insert a new line into the INVESTIGATION section and write Comment[myComment] in column A and test in column B
   c. Save and close the program
4. Use arc i edit
5. Close the text editor prompt
6. See error

Expected behavior
No error, normal behavior when using arc i edit

Screenshots

Additional context
Might be an error solely coming from ISADotNet.Xlsx but could also be a problem coming from how the ArcCommander uses ISADotNet functions.