I have no problems in leveling channel both trigger-wise and using OE...
that's what I mean, I don't have any icon problems with it... but if it turns green, then its most probably a case of unknown disbtn path (assuming it only turns green when it cannot be leveled)...
but if it also turns green if it can be leveled, then it means you forgot to put an icon on the Art - Research Button field on the OE... surprisingly, even if Channel is a hero ability by default, it has a blank research button field... which is why it's kinda easy to forget to fill up that one...