Solved in the first comment below. turn your input sound to 95 and sound on spearks lower, it drops out because it’s trying to sleep when there is no sound but takes time to wake up when it detects sound, this way it also has enough input to stay awake - Yes this is intentional by JBL! Complain to them if you can BA’d maybe they will give the option to turn it off.
https://www.youtube.com/watch?v=wOpC3-eNXec