The breasts fully don't work with all chest armor from Iron's Spells and Spellbooks 1.20.1-1.2.1 and Epic Samurai 0.0.26.1. The breasts are just purple.

They also don't work with some specific armors:
Rock Shell Chestplate and Unsettling Kimono from Alex's Mobs 1.22.6 (The breasts go through the armor using the pattern from the player's skin)
Crystalite Chestplate and Crystalite Elytra from Better End 4.0.10 (Same as above, I believe that the elytra part uses the model from the chestplate so fixing that might work for both)
Ignitium ChestPlate, Ignitium Elytra ChestPlate and Bloom Stone Pauldrons from Cataclysm 1.0 (The Ignitium gear has partial covering, but it doesn't properly match with the armor. The Pauldrons are bigger than the max breast size, but when bouncing they can sometimes be seen. Maybe adding in more physics resistance to them will work)

I am using Sinytra Connector 1.0.0-beta.13+1.20.1 to run Fabric mods on Forge 47.1.3. I do not believe that the Connector is causing these issues, however I will mention it just in case.

If anyone can direct me to the resources to fix this myself I am open to trying that.

Also, Lucky's Wardrobe (sometimes renders nothing, sometimes renders a seemingly unrelated texture). Also, [Let's Do] Beachparty, [Let's Do] Brewery also have issues, with purple textures, and with thing like the Dress and Bikini not rendering at all (I think because they aren't attached to the "body slot").

This is an issue I'd be willing to fix myself if I just need to add a texture, or something like that. But I don't think I'll really have the knowledge to. Also, this is not related to the Gecko issue Aceplante was having with kawaiidishes.

also KawaiiDishes, which apparently uses geckolib for armor rendering. He says the issue is on your side for "hooking onto the Minecraft namespace"

OHakimen/KawaiiDishes#16

forge 1.18.2