so let me get this straight, if I play Papal states and release a nation whose capital is now catholic, the nation gets released as sultanate and NOT as catholic bishopric?
Let's say I want to conquer Jerusalem area as Papal states (busy on it now), and in theory IF the Pope decides there should be a catholic Jerusalem nation as their vassal (sounds logical right, for papal states), then eu4 code sayss NOPE, Jerusalem, the holy place of catholics, is released as a sultanate?
Makes a LOAD of sense
My suggestion? If the nationalism and rebel chance of the force conversion to catholicism expired, it should be possible to release vassals of your religion in former heathen land.
Unless paradox admits this whole thing is a bug, of course.
I'm pretty sure the Kingdom of Jerusalem is Catholic in the history files, so no matter who releases the tag, they are released as Catholic, which considering how strongly the idea of a Kingdom of Jerusalem is tied to the Catholic faith, kind of makes sense.
From what I remember of the dev diaries, this was changed, because quite a few tags have strong ties to certain religions and to showcase more marginal religions like Judaism and Zoroastrianism. I.e. without this change there is no way to play as these religions without except by custom nation (dlc only), mod, or with some work religious rebels.
I can kind of get behind the idea, that tags like Papal States, religious orders etc. can't be converted to heathen faiths. It would be better though, if there was some way to designate tags as secular, so they can be released as any religion (probably not doable without changing the engine), or added some redundant tags with different religions.
As for people arguing, that it doesn't make historical sense, that tags released in converted provinces revert to the old religion... doesn't releasing a catholic holy order as a muslim state strike you as just a little bit more ahistorical. Along that same line, many of the tags have strong religious connotations, e.g. basically all the christian Kingdoms took their legitimacy from god. Most customs and rites, that made those kingdoms legitimate in the eyes of the people were heavily tied to the church. It doesn't really make sense historically, to be able to transfer that same legitimacy to a muslim king. The Protestant-Catholic divide historically strained that relationship quite a bit, it makes sense that Catholic-Muslim breaks it.
edit: Gameplay is obviously a whole other question, but the historical/logical argument against the change is pretty bogus.