Visio internal error #-1

[Visisthebest]

I am getting a Visio internal error #-1 working in a file where a lot of changes are made to the diagram.

Visio 2019 Professional latest updates installed.

Please see attached, the exact error is: Visio internal error #-1 action 1004:Save

I am not performing a save at the time, is there an autosave going on maybe?

Always good to understand Visio error to make sure underlying issues can be tackled.

Thank you for the insight!