I did a search via Google and in the forums to see if this is a reported bug and didn’t come across anything.
I’m using most recent released Windows version of Scrivener.
I’ve noticed when I open Project Targets to keep track of a session word count, I get spikes of “lag”/freezing while trying to use Scrivener. I can’t type anything, I can’t insert mouse cursor, can’t click on anything. These last about 5-10 seconds, then it’s back to normal for a little while before I get freezes again. I’m not sure if it happens while Project Target is trying to update itself or not but it’s frequent enough that it greatly impacts Scrivener’s usability.
I found that if I collapse the Project Target arrows so the word count doesn’t show, I don’t get the freezes in the main Scrivener window. If I close the Project Target window entirely, Scrivener is back to normal.