Guild Training at Dubious?
 

I remember back in the day on my Shadow Knight (dark elf) getting denied at the SK trainer in Grobb at dubious for skill training.

I've been messing around with an Iksar, got him to Dubious with Silent Fist clan, and was pleasantly surprised when they allowed me to train.

Is this broken, or is my memory garbage?

you can train even KoS here