Files save issues, Photoshop.

Hi, I'm running latest updates of Photoshop and MacOS on an M1 iMac. 
A new issue has recently occurred: the "Save a copy" dialogue intermittently fails to work: dialogue box appears as usual, and appears functional,  but the "save" button doesn't work (is not greyed-out, just doesn't work). Occasionally, resizing the window fixes it, but not always. The only way to exit the dialogue box is with the Esc key. 
Doesn't happen every time, but often enough to be annoying. A similar behaviour occurs with the File>open dialogue, but much less frequently. 
Restarting PS fixes the issue for a while. 
I know this was an issue with earlier releases, but thought this had been fixed?

Thanks.