This isn’t a bug. Game passes are no longer assets so you have to get the image separately using the new ID (You’re using the old one)
game:GetService("MarketplaceService"):GetProductInfo(3178145, Enum.InfoType.GamePass).IconImageAssetId
http://www.roblox.com/Thumbs/Asset.ashx?width=420&height=420&assetId=2431560854
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