Ok it just happened again!
This time in a BR.20 which again suffered engine failure (must be doing something wrong - found useful threads and info on this though, might be oil too cold and thus governor failure)
But, this time I DID record a track!
Could someone have a look at the attached track (just fast forward until I hit the english coast and begin an erratic descent from the clouds when I hit engine trouble) and confirm whether they see the literal 'warp' into the water at the end?
I find it hard to believe that no one has ever experienced this before when I've had it twice already! It's ruining my flights!