I noticed that on full servers it is almost impossible to skin animals or chop down humans for that matter,also drinking 100% from a bottle doesnt seem to work.
There is a rather strange way to perform such actions anyway (without resorting to the F11 spamming) Start skinning (or whatever action that only ends in "cancel current action") and immediately after that push "W",release "W" after you performed the action.Works on full servers everytime.
Not much of a bug,just a way to help some people out^^