When playing a Barbarian with WASD movement, Flay will occasionally attack twice in response to a single click when combined with movement and mouse position inputs. This can occur with Rend as well, and this is occurring without either skill’s relevant Temper (Flay’s is a Duration%, while Rend’s is a “Hit Twice”, but again is simply not slotted on my character).
This may be a new bug created by fixes to previous “Barbarian basic attack WASD” bugs that I can find which involved stopping animations or being rooted in place, but this is clearly distinct, with two full (and functional) attacks playing out, and normal movement resuming afterwards. It does only occur with a combination of click (once, clean) to attack, WASD away, and mouse away to another valid target.