Verin didn't channel in the stedding because only Forsaken and some really dark shadowspawn can use the True Source. And for those who says that Verin is a Forsaken well we learned that they are scearded to use the True Source so I don't think a Forsaken would risk use the True Sorce on a dumbass ogier and at the same time rasing suspition by being able to channel inside a stedding. Anyway I think that the True Source is related to the One Power because the first time Nynaeve confront Moghedien and shield her, Moghedien dosn't use the True Source. I think it's because she is shielded, when who are shielded you can't use the True Source. In a stedding you can't channel black Ajah or not and I think that it applays to the True Source also. Something strange with Verin is how she gave Egwene the ring, she forgets 5 seconds after Egwene left. Was Verin made give the ring to Egwene by somebody else, was she controlled?