3d Layered clothing not wrapping around body?

I have been clawing my eyes out trying to figure out why this isn’t working for the past hour or so, (yes, an actual hour.)
I’ve modelled a jacket in blender, and considering I deeply followed both roblox’s requirements AND used their example model, I thought I was all set. But I guess not. Whenever I try to equip it in game, it doesnt wrap around the body as intended, even while using the “recommended application methods” on the reveal post: 3D Layered Clothing is Now Available!
Yes, the “allowing 3d layered clothing” beta option is on and YES I have tried so long trying to find information about this, but other than some not helpful roblox articles and several devforum posts with no comments, nothing! There’s so little information about layered clothing too, there’s not a single video on the entire internet that’s a tutorial on this. Please help!

Also forgot to mention its not just this body type, any body type, rthro or classic, does this. Even the normal clothing items NOT made by me do this!

I will gladly give more photos or context if needed! TY!