Jumping tank

[fregate]

Hi!

I’m using UE4.13.2 and if I move mouse - tracks are going down a little and jumping (lifting) back (because collision bounds). And tank jumping a little - seems like trying to move (and if placed not in a flat ground it really moves because of gravity).
Is it engine issue, or I miss something? Because tank in lectures is stay still at playing and mouse moving. Maybe lift tank and all the parts up a little?

Thanks.

[fregate]

So I think, that happens because of position of an actor. I set it to Z=0, but tracks ends about Z=-5 and when game starts all the tank lifts at 5, but when I move mouse - it sets to Z=0 (tracks going down), after that - physics solves some math and set it to Z=5, but it seems not like just change coords, it seems like pops (bubble from water).
So if I set actor at Z=5, all works fine.