It's not really a bug. And it's not Sacchin related really. A lot of Arc Drives have last hits that are scaled to deal with the proration system that the game uses, since the last hit should do a few hundred damage. So they calculate how much they want it to do and mess around with it to deal with proration.
It's just really hard to actually get people to not be get caught in it. Sometimes you could do it by stretching it in MBAC 2v2 by airthrowing people out of arc drives. There's a lot of situations with Kohaku EX Bomb knocking her out of stuff that can't really happen. In vanilla MB version 1 there was the worst glitch ever: sometimes Warachia's Arc Drive was flat out techable and the last hit was invalid, but if you airteched it you'd take 11k instantly from the last hit. You can do it pretty legitly by EX shielding every hit of Wara's AD/AAD except the last one, and then taking the launching hit and the finisher for tons of damage too.
And I think there was a way for Len's AAD to go off without actually being caught in it. You couldn't do anything during it though since she's not on screen and it still goes black.