I went ahead and found myself a testing subject with full 512 body and joints. I deleted their custom folder beforehand to be sure, and then I let the game download the textures automatically.



As you can see in the first image, some of the joint textures are missing. You can also see from this screenshot that autoupdate is enabled. To make sure that it wasn't just that the game didn't download the textures in time, I waited until Pazzi has played another game.



As you can see from this image, Pazzi is still missing some of the joint textures, all of the leg ones except Right Glute to be exact. I stayed in the room for a while, but these joint textures have remained not downloaded. This can be fixed by running /dl Pazzi manually, but I shouldn't have to.

EDIT: I should probably also note that said joint textures were also missing from the custom folder, so the download did in fact not happen. The version is 5.5 on Steam.