I’m not sure why this would be. Some normal things to check:
Are the in-game graphics settings set to 10 and not auto or something lower? It seems like the lighting normals and stuff of the PBR aren’t being rendered, making it seem like this is possibly the problem
The following code can be run in the developer console to check if an asset has loaded:
local ASSET_ID = "rbxassetid://[YOUR ID]"
local ContentProvider = game:GetService("ContentProvider")
if ContentProvider:GetAssetFetchStatus(ASSET_ID) ~= Enum.AssetFetchStatus.Success then
print("Asset is not loaded!")
end