Players briefly freezing when getting hit by knockout powerup

[Scrotes]

When someone gets hit with the knockout powerup, all players in the server (or at least the recipient/dealer, it's hard to tell) will briefly hitch. This is normally not too big a deal, but its used in a minigame of mine where that brief hitch is often grounds for instantaneous death because players are repeatedly required to jump over a spinning blade that is moving at VERY high speed.

I have no idea why this happens, and I can't seem to isolate the cause. Console shows nothing of value, so I have no leads regarding this.