Update:
chkdsk would abort during its run, but did create folder called FOUND, so it was finding issues.

Used robocopy to backup as much as possible off mmc2 to my PC. Only a few files were corrupted and could not be read. The NoteCase auto-create-backup-files option saved my butt big time in this situation for my encrypted DB. The backup files all work and are readable on my PC.

Searched to find the best way to format mmc2 from the tablet CLI and found out that the issue I'm having has nothing to do with Notes app. m_stolle was exactly correct in their assessment of my issue.

Newbie ALERT! There is an issue with N810's internal 2GB flash memory. If you don't have corruption now, you may get it soon. Bug report is here. My allocated block size was the incorrect "1999206" as shown in the bug report.

Fix was done by following this post.

If I do a newbie perspective write-up of how to fix this issue, could the post be made into a stickie for the newbie group? (not a lot of stickies here and instead a lot of "use the search" messages ) I could have avoided getting corrupted files if I fixed this when I first got the N810 and I'd like to save others of the same or worse pain.