@GrungeQueef it's called "tea scum". It's not mold, it's chemical reaction caused by the tea itself, even unsweetened tea grows tea scum, which is why you should make your tea fresh like coffee.
@GrungeQueef if it's sweetened tea, then yes it's gone bad.
I drink herbal and green tea that doesn't have sugar, and it gets
"tea scum" after a few days if I don't drink it all.