It might have been me. It is not the only way that I get combos with the hammer, but it is one. I wouldn't go as far as to call that move OP because it's really just about timing. The Gladiator Sword and the Blade of Athena can do the same thing if the L1 Squ is timed properly.
I think I'll try to hold back a bit when it comes to the grapple L1 Squ. If the person does the Jump O reset on me, then I'll do it.