4.0.4RC1 GPS glitch

Raspberry camera cable can cause any kind of troubles to gps, you could try disconnecting camera and see if the problem is solved.

Could that be my original problem, I have installed 4.0.4 RC1/RC2 from 4.0 dev that I think I read is 4.1?

I have tried running it on the bench without the rpi on and I can see same behavior. It’s like this fw are relying more on the GPS speed than what Ive seen before. When the issue occur I have high speed variance, at least what I think
Testing indoor with fairly bad reception the gps-raw and global-pos-int follow each other pretty well when running 3.6.12. (without updating parameters after downgrade) no pos-int runaway as I seen in 4.0.4RC1/2
Another finding I got is that the 3D printed TPU box I made for the GPS seems to interfere with the gps reception. Got less variance in GPS speed signal just by taking the lid off.