Think this is new to the beta but when I ritually summon a pestilent scheme priest or doom engineer they are counting against my total number of priests/engineers. I thought they didn't count against the normal count you can use as agents. Maybe its been like this but i didnt think they did.
Played Clan Mors. Summoned ritual of doom and then when later upgraded building to support an engineer the cap was being used the the ritual of dooom engineer and I had no other engineers from random events. Similar thing for the priests.