Noisy heat pump— even when turned off and new onset crackling

I’ve living my building for almost two years and there have consistently been ongoing issues with the Daikin heat pumps throughout the building.

The two heat pumps in my unit (one in the living area and one in the bedroom but attached at the same point on the opposite sides of the same wall) have always been noisy, even when they are turned off. Usually the noises are humming and gurgling.

Most recently, there was very heavy rain and both heat pumps— while turned off— started making crackling/popping noises every couple of hours, for a few minutes at a time, even after the rain stopped. The volume of the noises varies, but usually there’s at least one or two louder cracks. I have never heard either unit make these sounds before and I am quite afraid of turning them on for fear that there is an electrical issue.

Unfortunately the building managers and company that own my building are not very helpful or responsive, so just looking for some insight as to how concerning this issue is in the meantime while I await a response on their end. Thank you!