When I copy/paste special the Modify Features window opens every time. Is there a way to turn this off? I have looked in the Project>Options with no luck. I also have an issue with the "Save Edits" window popping up even though my setting are not set to auto save. I am on Arc Pro 2.6.1 and this has been happening since two updates ago.
At 2.6, a change was made to Paste Special to make it consistent with Paste. When you use Paste Special, it now opens up the Move tool (on the Modify Features pane) just like a regular Paste did prior to 2.6.
Regarding the "Save Edits" dialog popping up, take a look at my comments in this thread, as it could be related to what you're seeing: edit auto save