Oscar promised to build a sept with the bones of the traitors...
Well, thinking about it, he's sort of an oathbreaker then. Because the Winter Wolves kept Cole's skull, apparently Oscar had no guts to order Roddy to give the skull back so he could build the said sept.
And for all I know Roddy dies before Oscar, meaning the skull never returns to him when Oscar fights the battle of the kingsroad. They might well build the sept, but it won't change the fact that he didn't use 100% of Cole's bones, because his skull is forever gone. Therefore, his promise wasn't 100% honored for a House which prouds itself of its honor.
That considering a show where logic exists ofc, but since logic and action-consequence doesn't exist in hotd, probably they'll find a way to teleport Cole's skull or smth.
