By the way, I see you've started a parallel topic in the NVDA Add-Ons Developer's group (Problem with Bookmarks addon in MS Word in Windows 10) and one of the actual developers of this add-on has requested logging data.

It's well worth hitting NVDA + Q, then choosing Restart with debug logging enabled from the exit dialog, so that you have logging information to send to the developers.  They may recognize what's up in seconds if they have that information.  This part of my tutorial, Collecting NVDA Debugging Information to Report to NVAccess, describes the simple steps for actually snagging that log data to send to someone else:

There are several ways to access the NVDA log  file afterwards:

If NVDA is still running and usable:
1) Press NVDA+F1 to open the log viewer
2) Press CONTROL+A to select all.
3) Press CONTROL+C to copy.
4) Press CONTROL+V to paste the copied log where you need to paste it. 

--

Brian - Windows 10, 64-Bit, Version 21H2, Build 19044  

It is well to open one's mind but only as a preliminary to closing it . . . for the supreme act of judgment and selection.

       ~ Irving Babbitt