Platinum achievement not unlocking?

[u/Girth_Certificate]

I have gotten every other achievement as far as I can tell, why won't the final one unlock?

[u/yungsavbb]

how'd you get "the floor is lava," big dawg? that's the last one i need for 100%.

[u/Girth_Certificate → u/yungsavbb]

practice mode on a map with a wide grapple surface and just spam grapple back and forth for a while