Does the default alien outfit have the same problem in a game with no CC in it? If it doesn't happen in a vanilla game, then it sounds like you have a CC clothing item that is broken or outdated which needs to be hunted down and removed from your mods folder. To test this, just rename or move your user folder out of the Electronic Arts folder and start the game. When you go to make the sim, choose to make an alien and dress them in one of the default alien outfits. Once you know if those outfits display normally or are still glitched, then you can exit the game. If they show up glitched in a vanilla game, try a game repair through Origin or the EA App, whichever one you use. If the outfits, display normally, then you'll have to go through your mods and CC to find whatever is causing the issue and remove it.
Hope this helps.
