They nerfed it a while ago but you could still chain heavy swings past what it was supposed to be able to do.
When they released the new power sword you could get unlimited heavy swings with that.
That’s all the ones I know about would not be surprised if there where more and since nerf ive had moments where ive had more swings than I was supposed too.
Honestly are you surprised by bugs etc? 
Bad implementation and bugs I can live with be patient while they fix it even help them with bug reports.
But if they are going to keep moving the goal posts on how weapons work with heavy handed poorly thought out nerfs like these in patch#7…
@ Mayson Did you watch the first video on the list by Claysthetics? None of your post applies to his video and your weird giga chad picture also makes no sense did you make that yourself?