Happens randomly, but when it does, it's a game breaker, especially in Battlegrounds with limited time and gear.
The staff simply stops working and instead of the heavy-attack animation produces a "hiccup" - character tries to reach the enemy player but fails and turns back.
@ZOS_GinaBruno I'd appreciate if you'd at least look at this. It's not that infrequent. Happens approx. in 1 out of 7 matches, no addons (except Master Merchant), PC EU.