I was present in this game, we had the same 4 people the entire time. While I can't confirm that it dropped from a lizard, the drop chart says Clio only drops from Del Rappy, and none of us saw a Del Rappy.
If this was yesterday, then you guys just need to re-patch on the patch server. There was a map data issue that has all the IDs off by 1. I think I sent an announcement about it.
Otherwise, you'll also have an issue when you kill the bosses in free-roam which will disconnect you for a map data mismatch.