At the moment there's nothing to tell you that another civ has potentially already reached that tech first and it's the FIRST to reach a normally religion granting tech that gets the prophet only. So I suspect it's not actually a bug. Yes, some work needs to be done to let you know when the religious tech has already awarded it's free prophet to the first civ to reach it. If you KNOW for sure no other civ could've reached the tech before you then perhaps there's something to look into. There shouldn't be any conflict with the other two processes though as they don't take place anywhere near each other in code. One bug we noticed the other day though: 4 generals were suddenly born in one barbarian city on the same turn for some reason... is this somehow intended design?