Sub fades in and out randomly

I've had an ongoing problem where my amp will randomly start blinking the protect light consistently until I turn the car off then on. This causes the sub to turn on for one second and off for one second in a continuous loop. The speakers still produce continuous uninterrupted sound though. I have no idea what's wrong I've tried 3 different subs and they all produce the same outcome, it could be the amp, but sometimes I listen to music for an hour straight without it acting up. See video attached for clarification.

View attachment 0614191855(1).mp4