String stretch.
Time for new string and cables
This typically happens from having new strings in my experience, not always from needing them.
If I ever get a new string and the peep rotates then I send them back because something is wrong.
My peep never rotates until the string is getting worn out and starts to creep or stretch. You can add a twist to get it back where needed, but it will continue to move and be a problem. So it's time for a new set of quality threads.
We are dealing with totally different materials the we were twenty years ago. At this point once the material is strcehed under tension it should be done for life of the string.Maybe I'm old school with regards to technology but years ago, the tightest a string was ever going to be was when it was new and every day thereafter it was going to stretch and the peep was going to settle. It was a very common experience.
You are correct that is how it used to be in the 80's and early 90's. It doesn't have to be that way now. With quality string and cable materials and built properly they don't do that anymore. Once I have my new set installed and the bow in spec my peeps don't turn at all. There is no settle in currently with quality sets. Once my peep starts doing that it's time for a new one. They last for 1000's of shots with no peep movement as long as everything is done correctly including tying the peep in properly. If you tie the peep in wrong it can cause peep rotation.Maybe I'm old school with regards to technology but years ago, the tightest a string was ever going to be was when it was new and every day thereafter it was going to stretch and the peep was going to settle. It was a very common experience.