Walking with 3 m/s
When I landed with my jetpack today I suddenly could only walk 3 m/s. Crouched it was 2 m/s and running diagonally 6 m/s. Normal running 10 m/s. So running was ok. I switched to jetpack and back a couple of times but that did not help. After some minutes the bug disappeared. Not sure whether I did a quickload.