First case: it is possible that use of the derived material, in the absence of a licence, could make a publisher liable for infringing WotC's copyright.
Second case: WotC has no contractual relationship to either licensor or licensee. But those two parties have promised one another, under certain circumstances, to reproduce the text of the OGL v 1.0a, over which WotC claims copyright. So fulfilling their contractual obligations to one another may oblige them to infringe WotC's copyright. But there are probably arguments available that they enjoy some sort of express or implicit permission from WotC to reproduce the text of the OGL v 1.0a (eg based on WotC's conduct encouraging other parties to join the open RPG movement).