What is making the AI remove their state religions from their cities?

[Theophilos]

I see again and again the AI somehow lose in their city their state religions. For example, Sindh lost shia in two of its cities and then converted

Egyptian cities somehow becoming Catholic only cities

Could the religious persecutor be bugged for AI? removing religion at random, even state religion?

 

[srpt]

the only coded religion removal I'm aware of is for the decline of Buddhism.
can you post a save from just before the religion is removed?

 

[Theophilos]

the only coded religion removal I'm aware of is for the decline of Buddhism.
can you post a save from just before the religion is removed?

Playing further, I think it is not that it is being removed, but rather the AI never seems to build missionaries (or if they do, it is rare).

They do seem to build religious prosecutors, though.