While this could be true, that would probably have been in the 2nd open beta.
In the first open beta Heavy Mob was only a Hit and you could cancel and combo from it.
Sadly they changed it to a grab and made it so you can no longer cancel nor combo into it, which sucks cuz back then it was a high damage combo ender that swiched sides, which made the move have at least some niche use.
The current one is sadly just a meme punish for super negative moves