I also had this bug today on same full server on Myshkova River map, I was allies tank commander, and I was stuck at 10Km/h for a long time I change to incremental throttle then switch back to no incremental throttle but it has no effect. Then after a minute or two messing in the map to go on E objective where I finally stopped, I got teleported back in spawn, where I actually was stuck because of a little object... (for me I was slowly driving in the map but for all others I was not moving near spawn where I was stuck because my track/tank got stuck in something). I then was able to drive at normal speed. Similar bug, but this is another way to trigger it.