Death By Disco Achievement (R&C 2016)

I recently came back to the game and there’s one achievement that’s stumping me while trying to get the platinum.

to unlock death by disco you need to throw a groovitron at every enemy in the game, sounds simple right? nope.

i have played through challenge mode 3 times now and made sure to throw a groovitron at EVERY enemy and yet still, the achievement has not unlocked.

i’m not sure if this is a bug or if i’m repeatedly missing one enemy but i’ve done everything from veldin to your second time on the deplanitizer.

is there something that’s kind of hidden that i might be missing? my first challenge mode run was 100% (wrapping up from story mode and unlocking omega weapons) and these last 2 have been quick (still like an hour and a half long) just to make everything dance.

would like to know because i’ve just completed my 3rd go at this and the enemy i thought it was apparently wasn’t it.