The issue of PlateSolve2 mysteriously reverting from what ever the user has set it to, to 3000 regions (Max Regions setting in Control Pannel) has been around for a while but I have finally seen at least one thing that is causing this to happen – it is the use of the “Solve and Sync” function in the Scope Centering module.
I set Control Panel (in the Sequence file) to a value of 100 Regions and did a Solve and Sync. PlateSolve2 popped up showing the correct value of 100 regions. A few minutes later I happened to run the Solve and Sync again and PlateSolve2 popped up showing 3000 regions. When I re-opened Control Panel, it had been reverted to Max Regions.
I was able to verify this sequence of events by running the Solve and Sync and resetting Control Panel several times. I am using 18.104.22.168 but it is likely this has been an issue for a while.