I took four flights with my p4 with stock battery, then I took it completely apart and wired it for external batteries and put it back together. The very first long-range flight with it modded was perfectly normal from the start, took it out of 44,000 & back. That was yesterday I landed and packed it up like normal. Took it out today for another flight, flight number six, I got messages on the screen where you normally see "safe to fly GPS" that read "forward sensor calibration error" This only happens after I wait for safe to fly message and as soon as I lift off into the air! Just to be clear, I fly with the sensors turned off in the app .Upon inspection I noticed this, One of my forward sensors is not sitting perfectly centered in the shell. It's hard to get a picture of it that small but I think you get the idea. I have to assume this was like this when I put it back together and it didn't affect the first long-range flight at all. Any ideas, other than the obvious to take it apart and realign this.