I am having the same problem after thoroughly cleaned the wetside as well. The dryside somehow popped out from the spacer and swinged to other side of the tank, and because of this loss of magnetic force, the wetside slowly slide down to the bottom of the tank. It happened 3 times already after the wetside was cleaned. I am not able to update the firmware as it is controlled by Profilux.
What I just did a coupe of hours ago was set the MP40 to operate on 1 mode only (it used to change mode every 2 hours) and it has been fine since then. I am going observe for a few more days.