Play Anim Montage causes infinite loop

I have an Play Anim Montage node set up to play in the event that the boss’s health bar reaches zero. When I try to play the game, however, it refuses to launch, citing an “infinite loop” with the play anim montage node. As shown in the included video, the anim montage does not actually lead to a loop, as nothing branches off from it to repeat.

While I was in the process of writing this question, I deleted the anim montage and tried to play it again. This caused another error message, citing an infinite loop with the do once standard macro, which I have not edited at all. I hope this is able to be fixed. If it’s any help, I have two other characters that work flawlessly with the same bit of code that seems to be bugging out on this one character. I can provide more images if needed.

You didn’t provide any clips or images, so it’s hard to help.