players spawn as grey blocky characters in my roblox game

there's an event made for this, player.CharacterAppearanceLoaded. hook your spawn stuff to that instead of CharacterAdded and it waits until the clothes and accessories are actually on. maybe add a timeout so a slow avatar fetch doesn't hold the player up forever.

sounds like the character is spawning before the avatar appearance has finished loading. on a full server that fetch is slower, so if your spawn script moves, scales or swaps parts the moment CharacterAdded fires, it can end up working on the blank body. try waiting for player.CharacterAppearanceLoaded before touching anything. if you've turned CharacterAutoLoads off and call LoadCharacter yourself, look there first.