Metal Gear Solid: Peace Walker

[Paar86]

I have a question about the game. I've tried to play PAL version in the PPSSPP 1.7.4 and apart from rare texture flicker while crouching I noticed some werid stuff going on with the first boss (armored vehicle) physics. The vehicle sometimes tilts to the air like it was stuck on an invisible hill. It's movement is unpredictable as it changes speed from slow to fast instantly. Did this happen to you too? I'm using Vulcan renderer.