Hi. Today I randomly stumbled upon this by accident, but it seems like Zamazenta loses his Behemoth Bash move if he enters a battle for the 2nd time. I assume this is a bug, but I could of course also be wrong.
Dauntless Shield does seem to activate again if you switch in.
(If this is by any chance a duplicate report, then I apologize and you may delete it)
Sequences I've tested:
Zamazenta starts combat, has Behemoth Bash
Switches out
Switches in
Zamazenta has Iron Head.
Other pokemon starts combat
Zamazenta switches in, has Behemoth Bash
Switches out
Switches in
Zamazenta has Iron Head.
Screenshots:





Optional Gif:
https://gfycat.com/pitifulmintyborzoi.gif