I noticed only roman province of gaul, and concilium britanniae in briannia, can come back to paganism, building old gods temples.
while romano-british factions can choose only between roman christian, and pelagianism.
why? usually with these two more "civilized" factions (romani in gaul, and concilium in britannia) i slowly come back to paganism, building temples and slowly destroying churchs, but with dumnonia or eburacum, or votadini, i cant do it. ok even votadini, guened, ystrad clut etc didnt thrust much in roman paganism,but at least in celtic yes i gues, since aegidius in gaul, and romano british lords, was constantly in struggle with druids that walk in forests, etc etc (often they found offers to gods, etc etc in the forests, and bishops complained many times with the authorities because "evil pagans" turn outside cities.).
some dev can explain me why please? just wonder the reason of this choose in the mod. thank you.