Check-in of wireframes with screenshots in MacOS Big Sur

I am not able to do check-in of wireframes (teams project), when the wireframe has any type of picture/screenshot used in it. As soon as I remove the image(s), the check-in works again. Otherwise it fails with an error.
Seriously: if the quality of that product goes on like this, every single interaction designer in our team will abandon Axure in favor of other tools. Even now, I am kind of the last man standing - defending Axure as a prototyping too.

Addendum: I had a switch regarding the company protections suite from Symantec to Microsoft ATP. After the change, my check-ins work again. Not sure if this is correlated - but it would be quite a coincidence if not. Did not change anything else.