Having a too tight grip is the same as having a grip that is too tight on a bar.
It doesn’t allow the handle of the KB or the bar to slide through your grip.
A grip that is too tight can activate muscles that aren’t involved in the movement. This can causes deviations in the movement patterns.
If you are bruise across many different sets of circumstances would be beneficial to get it check into.
It could be an iron deficiency which that when addressed resolves itself.