I played as macedonia and used the colonists from Korinthos in 1st turn. Everything is right.
At the 8th or 9th (don't remember) I was able to build an additionnal colony. Since Adviser told me nothing and it's not an olympic year, I launched a building and canceled it to get rid of the colonist. (A matter of fair play)
At the 16th turn, I gained no colonist.
At 30th I conquered Athenai, a 2nd metropolis.
At 33th I got only 1 colonist instead of 2.