There is a Christmas deer by the main fountain in monquista city that continues to drink from it to all eternity. Certainly not a game breaking glitch, but I though I'd mention it.
That's only Olive, the other reindeer. She's just early for Christmas in July. However, Olaf, the snowman who was in the watermole village in Skull Island, has suffered a serious accident. Apparently he got one too many warm hugs and melted completely away! All that's left of him is a tophat and a carrot. ( Find his remains behind one of the palm trees tapped for sweet sap. )