"Beeping" noise when water heater is running

[CortezCapt]

The only way I can think to explain it is as a beeping noise coming from the propane tanks or regulator while the water heater is running ( gas only water heater), while plugged into shore power. The water heater seems to be running fine though haven't run it for any extended time yet. ( Our first real shake down trip this weekend as been placed on hold due to my grandfather being admitted to the hospital for quintuple bypass). However I have been getting everything set up and sorted so when we are able e will be ready.
The fridge works off of propane with no beeping noise. The noise is not so loud as to bother us inside and not the propane alarm, but can be heard outside near the tanks. Not sure if this is a normal thing or maybe a regulator going bad ( if that actually happens) . I'm not that familiar with propane other then the basics lighting a grill or stove ( and not tend to be very cautious with any gas ).
Any ideas or suggestions would be greatly appreciated, and I apologize if this is a repeat question on here.

[monkey44]

Ours does the same thing, usually when more than one gas appliance is running.

It sounds like gas is just 'squealing' through the lines or the gauge, and is not causing any trouble. It happens more often when we run the WH and cooking, or if the fridge and WH run at the same time.