Whatever it is, it doesn't sound good. I recently upgraded a panel in our guest house with Arc Fault (AFCI) to address any "lose" wiring connections. I also replaced most of the old school wire nuts with these - Wago Level Nuts
https://www.wago.com/us/lp-221Solves the loose connection issue.
those look pretty cool. did you buy them locally or online?
actually looks like home weblow stocks them.
Hah, actually used some of them today for the first time. Had to add onto a string of 5” recessed cans and figured it would be easier to use those instead of trying to install wirenuts through the can interior. They work great. Now back your regularly scheduled program. Dave
