Oil in the coolant system

[Javromerov]

I have a Forester with the FB25 motor and few days ago I find out that the oil from the motor was going to the antifreeze after that we stop using it and later we noticed that the antifreeze was going back to the oil, but this did not happen in the beginning. Now I did take apart the motor totally thinking that the head gaskets were the culprit but no, they look totally fine.
I thinking that it my be a pace where is a crack o a o ring broken.
what you think guys?