Hello!
Don't know if this is correct place to report this (I was considering both github:c172p-team and FG's sourceforge).
I have an issue with the autopilot since FGdata (https://git.code.sf.net/p/flightgear/fgdata) commit fbf4be91e32db5dbd0d3df42bdb5c4e19bb0a771.
The problem: the Arm/disarm button does not work correctly in the 3D model. To activate the autopilot I instead need to open the dialog window (F11 key), change the barometer pressure values, then click "AP". After that is is possible to de-activate the autopilot in the cockpit (without using the dialog) which is at it should be.
But to activate it again I must once again open the dialog and press "AP" (no need to set pressure again).