Well, it means some religions might never get founded, if the founding wonder is build it worldbuilder. I decided to add some python code to make those wonders add the religion/set the holy city each turn to make sure ti does not happen, but running it like that could be a bit inefficient. Normally it happens when loading the mod, but I've seen it when starting a new custom game or loading saves too. In my current game it happened when Auric Ulvin entered the game at the completion of the White Hand ritual. I got an assert showing a problem with Auric's leaderhead art file, and then when Auric tried to contact me the game crashed. Fortunately I had a save from right before the ritual was completed. When I loaded that to try again I did not have any issues.