I tested it out if it still happens without any mods. ANYONE can still easily reproduce the glitch on the GIF in vanilla games. Just equip any jaw-stab available weapons like hunting knives, try to perform a jaw-stab from the front. Originally, if you attack too early, jaw-stab does not trigger. If you attack too late, jaw-stab triggers but immediately countered by zombie's attack and perform a repel animation. On current build, the latter one does not happen(well it sometimes do happen but usually it doesn't. I don't know the exact condition, tho. When the latter situation happens, the glitch above does not happen). So, no matter how late you trigger a jaw-stab, it just ignores the attack from the zombie, and execute the target. Instead, the repel animation is somehow 'suspended' till you perform a 'close window', 'sprint' or 'push through' animations. You can even test yourself if you don't believe me.