S1100 trouble

I have a problem with my S1100. Air direction, Air Speed, Ground Speed and Altitude screwed up 40 sec into the flight. The s1100 flew flawless before this flight. Engaged Cruse Mode at 1:27 into the flight and it later banked to the left so I switched back to FBWA mode. Before landing, it oscillated on pitch axis. Altitude is still going down even after it landed.
Gears I have onboard
Matek F405-wing with Arduplane
Tekko 32 Metal ESC
BN-880 GPS
R9Slim+
800mw 1.2ghz VTX

[@HermyH66]

Looks like a sensor acting up, barometer perhaps? Definetely would swap the fc like you said.

[@MyRazerZone]

Thanks! I got a Bnew F405-wing waiting to be transplanted :D

[@fndfpv3678]

Hi, good job . Whats camera are you using ??

[@MyRazerZone]

Runcam phoenix 2 nano. Thanks!

[@EnglishTurbines]

Oh, too much gain on the pitch maybe?...

[@MyRazerZone]

Not just that. Keep an eye on altitude. Negative altitude then kept on going down even already landed 🤣

[@EnglishTurbines]

@@MyRazerZone Yes, I noticed that too...FC not up to it maybe?

[@MyRazerZone]

Yeah. I guess the FC is going out. I got a new F405 wing on standby. I'm going to rebuild her.

[@EnglishTurbines]

@@MyRazerZone That will do it for sure on Arduplane....