For me, it only seems to happen when I have my identical Flip 4 speakers in Stereo mode, using the JBL app for Iphone SE. Hadnt used stereo mode in some time and when I went to use it today, I got a message to update. I updated both speakers, rebooted the phone and the speakers and still getting speaker interruption of mixed duration after 10 minutes or so of playing just fine. Several times, the JBL app said “trying to find devices”. Strange to me, when just minutes ago, it had found both, identified them by color and was playing fine in stero.
I have not tried doing factory reset yet. I am on the latest iphone IOS. There are no other bluetooth devices in range for the phone to connect to. I will keep you posted.