PX4Flow field of view change problem

Hello, I got a new PX4Flow which works great, BUT, I changed the lens from 16mm to 11mm.
I tried to change the FOV value in mission planner by connecting to the PX4Flow via the USB port. after I clicked change parameters it seemed like the parameters have saved, but after re-reading the parameters it changed back to the default ones.

when I tried to fly the drone with the default parameters and the 11mm lens using the optical flow, the drone started to move in circles which seemed like the drone would crash, and I switched back to GPS.

As mentioned before, with the 16mm lens it works great.

mission planner V1.3.77