It just means that you have enough research stockpiled to get those techs instantly, though I don't actually recall if that happens right as you click them or you need to actually pass a turn anyway. Or do you mean that they're stuck and do not progress even after choosing them?

They are just all set to zero, you click on them and get them all in the same turn. Going from tribal to first settled era shouldn't allow that. So I presume it must be some bug, probably from an outdated mod?

Having the same issue.  Have also been adding and removing mods to find out which one is doing it and so far nothing.  You ever find out what was responsible?  Really sucks since everything was working stopped playing for about a month came back and the game I was in now has all research cost nothing.

Not sure - are you playing with a calendar or era star mod? It might be one of the two.