What you failed to show in slow motion was your reaction delay to the left light. You were in top guard when the indicator showed a hit comming in left. You didnt switch guard until that hit was basically on you. The game has a guard switch delay that does leave you open to attacks. So all Im seeing is the game working as intended. If you had switched guard at the start of the left indicator you would have blocked. Showing that your guard indicator was on when you got hit isnt the full story because its about when you got there that matters.
^ Uhh, no. He switched guard fast enough. All there is to that clip is that he performed some action before that light connected which disabled his guard. You can see how his stamina drains a bit almost exactly when the hit connects. My guess would be a failed parry attempt, but it doesn't really matter - it's on him, not the game.