It seems successful parrying gives the player 2 seconds of 100% critical chance. But if the player parries again "before" the 2 seconds buff ends, the duration does not refresh until the previous buff ends.
Footage :
Steps to Reproduce
1. Parry and gain critical chance buff for 2 seconds
2. Parry again before the buff ends
3. Second Parry does not gives another 2 seconds of critical chance
A developer has marked this issue as fixed. This means that the issue has been addressed in the current development build and will likely be in the next update.