Same problem. I will power cycle my IceCap 3k Gyre and it quiets down. 5 minutes later, it's back to its irritating loud hum. Sometimes, it will switch off entirely, with no warning. The issue began a week after purchasing new from a reputable on line distributor.
I have never had to worry or think about the other pumps on my tank, aside from regular monthly cleanings.
So far I have updated the firmware and cleaned it reassembling according to the instructions. Has anyone figured out how to fix this annoying issue?