Free speaker tweak that's a must do

Most speakers should be tightened every 6 months or so depending on how loud they are played.

Only in case if you receive ones with ones that you can unscrew with fingers.
Overtorque may be worse than under.

I would suggest using a non-magnetic screwdriver. Some driver magnets are surprisingly strong, and can seem to reach out and grab a screwdriver, leaving a punctured driver in it's wake.

I never ever had a issue with it. And I've owned 100s of loudspeakers. Built many more. Most can and do play at SPL Polks could never approach. I do know once you've over torqued a fastener your going to have it loosen up and this is what Polk432 is probably experiencing.

I remember this happened all the time with the ProAc speakers I used to have. Never occurred to me to use something like Loctite on the screws :-(