Mouse movement (on desktop) becomes erratic after a day or two, have to reboot to fix.

I'm using Catalina on a desktop. Sometime around February I noticed mouse movement becoming erratic after about a day or two. Restarting the computer solves the problem but it recurs. I tried starting in safe mode and the problem is gone (BTT doesn't activate at login in safe mode). Prior to February (est.) the problem didn't exist - possibly related to an update?