I’ve got the same problem. I have two Oticon Engage aids, one PP(105) in my deafer ear the other not PP but (85). Recently they have started spontaneously switching themselves off then a few seconds later they often ping back into life. Repeatedly !!
In my case the right ear always pings first but I don’t know if this is significant. I think moisture getting into the aid may be the culprit. I have silica packets I store with my aids overnight and these are in now the microwave getting reactivated so hope this may help. Have any other solutions been offered ??