Clipboardic shows the following - the first entry is Screenshotcaptor automatically copying the image to the clipboard -
The 2-5 entries are Snagit pasting entries.
Not sure why Snagit copies 3 times but the type of media looks to be the same

Thanks for the continuing work on this Ian. I can't get the original fix to work on most/any of the notebooks now - I'll have to try it on the original notebook on Monday when I'm back at work.  I have tons of Onenote notebooks that I use - most of them are (and have been for almost a year) on Sharepoint. They are 2016 versions - I'll run some checks on a variety of notebooks next week and report back.

I checked on Monday - yes the onenote is 2010-2016 version and it's the same notebook that I was using where it worked for a week or so. I generate weekly reports for a status meeting and copy/paste web pages into the notebook so we have a historical record of stats for each week. So it's the same procedure every week.
I checked on a brand new notebook stored locally and a variety of other onenotes, most of which are on Onedrive and all generate the same symptoms.
It's weird that Snagit works correctly but ScreenshotCaptor doesn't with the same capturing of the region.
As it's the office365 version of Office, the client might have upgraded to a different build. I just ran an update to get the latest version and we're now running at version 1708 Build 8431.2270 Click-to-Run.

In case it matters after post capture I have play capture sound, auto select active window, but not if full width/height, Filename Balloon tip, add border and add Drop shadow to image.

Yep. @mouser, do you have any ideas why screenshotccaptor is appearing as a different format on the clipboard to snsgit?

@absoblogginlutely: This sounds rather like a classic state of minor instability in an operational system that is in some form of constant dynamic change. (Not a steady state.)