(edit: i resetted and it was fixed, i just had the idea of it, this post isnt deleted because theres other bugs listed)

(other bugs I found: Kerfur sometimes goes spinning in a small circle at random times, It just happens randomly, idk what causes it but hes not wet when hes doing it.

Noclipping then unnoclipping results in violent camera shake until you renoclip, Ragdolling while it does that will violently fling you across the whole map and will definitely kill you if you don't have god mode on.

Sometimes, when an slapper (Ariral) hits you, you get flung violently, and in most cases you die. I'm not sure what causes this but I was running from an Ariral when this happened (also around the force of enraged Kerfur-O kicking you).

When an Murder-Kerfur is sent to phase 3 really fast (I did it by spamming landmines with the spawn menu.), It forgets to adjust the audio and plays the original Phase 3 music.)

Vielleicht  Maybe you have activated the 'new' setting, or ''another one''.  Idon't really now, but there's a setting who can do this with controls, (in the "game" section in the settings).
Another problem may be if you are* on the experimental version of 0.8.2 .                 {Ps. srry for bad english].).

You might have activated 'Alternative interact (experimental)' in the settings, it changes how the controls for various actions work, and your descriptions of your problems match up with it.