FW drifts after launch

First, sorry for lack of description. I’m new to here
I have fixed-wing drone and we hand-launch it. It flies well but I have small problem.
After it is launched, it drifts almost immediately. Angle or depth(width?) is different each time I launch. It only happens in Mission mode
It happened for few months, I had another problem so didn’t think about it but I think it is time to fix it. Help me please.

plus
I looked log, I threw it straight forward but setpoint was set to wierd place (for last time it was 43 degrees right)