Not a game-breaking bug, however I have a little collection of frogs in my Minecraft base and made sure I had at least one of each type. My only temperate frog was named Slippy, and now she is a warm frog. My cold biome frogs are unchanged, and my base is in a savannah biome. Found at the start of 1.20, unsure if it's still an issue but I will update if I end up hunting for another temperate frog.