Hi
I rewrote lot of things on the server to make it faster. One mission that was clearly problematic was the Zep mission. It is now fixed but it will require an update on the phone to be fully ok.
A side effect of the fix is that when you hit the zep (the propellers or the main body), it won't light up on yellow. You are hitting it fine but it won't display on the screen until a few seconds later. You'll get your points and all, don't worry.
This is fixed on the next update.
The positive thing is that the zep mission now doesn't provoke almost any lag compared to before.