Chill Haze! It’s part of whatever you used to make the tea. It’s actually common in beer brewing too, certain malts create a haze in the beer when it is chilled. The exact chemistry behind it is beyond me, but it’s caused by something in the tea leaves / seeds / herbs itself that causes it. In the case of high level commercial brewing, it is often extracted to give a clear transparent color to the beer, but in cheaper beers and home teas, it’s not worth it since it doesnt actually affect the flavor at all.
Misconception: It’s related to brewing temperature. “Cloudiness in tea is caused by caffeine and tannins bonding with each other when tea is refrigerated or iced. The hotter the original brewing water the more caffeine and tannins are extracted from the tea leaves, and the murkier the beverage will be.”