Parry not working with Pulverizer or knife

I am unable to reproduce the bug but has occurred several times by me and a friend.

Basically the parry system does not work with either pulverizer or the knife during game with all zeds. When I parry correctly the damage reduction from any foe is not there and I get full damage dealt to me, as if I was just standing there. At first I thought this was simply just lag and I was miss timing the parry. But this happens with all zeds i.e scrake, FP to crawler. I then tried to keep my melee weapon (both pulverizer and knife) in the permanent block position. Now normally at this position you will still deflect some damage, but instead they go through you like nothing was there to block. As when I am parrying either Scrake or FP and I time it perfectly I still get a massive hit instead of a reduced hit to me. I have not had this bug with crovel or katana as I rarely use them.

Note this was an online game

No idea how to capture this as a screenshot and I don't really record my games. Has anyone experienced this bug before?

Parry not working with Pulverizer or knife