Tetrakarn sometimes doesnt work?

[MetalAtlas]

So im fighting the dragon in the Tower of Insolence and when i apply Tertrakarn to a character, it only sometimes repels when the dragon uses Lonesome Claw on them. I thought maybe i was just gaslighting myself to thinking it worked and maybe that move was like Almighty Physical, bypassing the barrier, but from what I see, it isnt. Has anyone had instances of Tetrakarn just not working sometimes? (I know it goes away after a turn, and I know which Ally Im putting it on, dont worry i made sure to double check everything to make sure i wasnt just being an idiot)

[steven]

Loathsome claw is an Almighty Physical Slash attack.
Tetrakarn (at least in previous games) doesn't block Almighty attacks

[IHOP_Pancakes]

Doesn't work against the ice dragon either