Thanks for the troubleshooting advice, I will try this method on several other cards with the same issue.
I know this might be redundant, but the body/bra alpha mask varies quite a bit depending on the clothing (even if you paint a few pixels green or yellow, you'll see the effect of the body piercing through the clothing, or, as happened just now, the floating arms). But here's another tip in case you're unsure how to position certain body parts and want to modify the body alpha mask for this model or any other you have or create.
Use the body's UV map, but be careful; when you export the UV map, you'll see that it comes in an exorbitant resolution. However, you can fix that by adjusting the resolution to that of the body alpha mask.
Now, if I mentioned these image editors, it's because they can work with layers. Of course, there are nuances in how they are used and the options and functions they offer, but the idea is to be able to use the UV map so you can identify which body parts are being hidden or shown (generally, only what is hidden matters, which is why most of the alpha masks you'll find are mostly yellow, with green appearing in the minority).
You can extract the UV map using the Material Editor or in the Overlay/Underlay menu for the face and body. The Material Editor's UV map is a PNG, which may be more useful for its transparency. The overlay/underlay doesn't; it uses a flat white background, though that's up to you.
I'm sharing both formats with you.
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I'd also like to digress from this whole topic: there are those who use modified bodies, such as those from Dragon Ball, which, if I'm not mistaken, were modded and extracted from Xenoverse, and Koikatsu doesn't support them despite the fact that they're such elaborate mods (which is why almost all the clothes you try to put on them won't fit), but I think they've already worked on a bodysuit (a zipmod) that fits well with this body type. I also mention this because this body uses a different UV map, and therefore, another order to color the body alpha mask. I know it's irrelevant, but it never hurts.
Well, now I'm sharing this little contribution with you.
(If you have the Material Editor components and the over/underlay, you can also extract them to your game folder (one is created for the overlay and another for the textures or masks you want).
I forgot to mention something: most, if not all, of the Koikatsu models you'll find, regardless of the version you have, will use always this uv map, I mentioned that dragon ball body mod because it may raise doubts, but in itself, if you use any other body, even a mod, you will see that they use the same uv map or similar ones (like Body:amputed).
(Sorry if I went on too long, I just wanted to cover your question and most of the questions that may arise later, or for anyone reading this thread). 😁
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