I bought a P4P+ 3/15/19 and on 3/31/19 the EXACT same thing happened to me, in a place I frequently fly my 4S without issue. Fit the strong interference message as well and black screen. I Always fly los so got home fine. Checked everything. Rc, bird and Batts on correct firmware. Cleared cache. I DID see that the actual go 4 app needed to upgrade, from within android. Did that and no more issues. Did/does your actual go 4 need to be updated? I know, dumb question, but I had to digg to f find out mine needed to. Would love to know if you find a solution!