Progressive EMS-HW50C unit

We have Porgressive EMS-HW50C about 1.5 years old and hardwired at the dealership into our new camper. Yesterday about 1:00 a.m. we heard this loud tapping noise. We thought we had a large rat in our wall at the rear of camper, but there is no way for anything to get in underneath back there and nothing could be in the wall. Finally narrowed it down to coming from under the pantry so took out bottom shelf to expose the Progressive Power Manager. It was coming from the Progressive device. It would stop and later start back up again. It would go thump and then start in with this erratic tapping or thumping noise. You could even hear it outside the camper with a generator running. You could feel it vibrating the wall. No errors or strange readings on the LED display. It did this off and on for a couple of hours. Called Progressive and he asked for error read-outs. He said there was only electrical components and no moving parts inside it other than a switch. He said to call them back again when it began again. It has not done it since, but we still have the area where it is opened up.

Has anyone had this happen with their hard-wired unit? Everything appears to be in working order.

Thx