I've had similar problems flying all around Europe as Star Gold. Much of the Star signage doesn't have the CO logo on it. I have had fast track denied a few times, though it is getting better, except with Brussels Airlines for me.

The boarding order has been hit or miss also.

I think the OP understands CO doesn't control immigration/emigration controls (I hope he does) but is just noting that due to that delay, he missed his boarding group, and was not allowed to cut in like stateside.

Ciao,
FH