Something seems to be really wrong with religion in this version. Here is what happened in my Rome game:
XXXL52Scenario, I developed quickly, got entire Italy, Magna Graecia and Gallia Cisalpina, something about 18 cities, in that time I also had a single war against Salluvians. Got a single Emigrants and I've decided to settle them in what basically was Naples. At that time no religion was present in Western Europe, no Nordic or Celtic. But as soon as Nordic religion was established a weird stuff started to happen. Every city not only in my civ, but also in other civs that were fighting and won against countries that converted to Nordic, flipped to Nordic at growing a new PoP. In just 30 turns, every single city in France, Italy, Germany and Spain was Nordic.
I assume that this:
-) Python: Emigrants spread religion too
-) Python: Settlers spread state religion when city is built
-) Python event: refugees come with religion too
Is responsible and honestly it makes mod unplayable in current state.