This is from the EU draft mandate for negotiations with the UK:
Should a dispute raise a question of interpretation of Union law, which may also be indicated by either Party, the arbitration panel should refer the question to the CJEU as the sole arbiter of Union law, for a binding ruling. The arbitration panel should decide the dispute in accordance with the ruling given by the CJEU.
What exactly do they have in mind here? At the WTO, when there is a question of the operation of a domestic measure, it's a factual question for the panel to decide. (There's some debate about the nuances of this, but they don't matter for the issue at hand). Surely the EU doesn't mean that an EU/UK trade dispute panel could not try on its own to figure out the meaning of the law in question for the purposes of deciding whether the EU measure violates the agreement?
My understanding from some folks on Twitter is that this provision applies when EU law is explicitly incorporated into the trade agreement, and it has been included in EU association agreements before. But I'm not sure about the universe of situations the EU has in mind for referral to the CJEU, and I think they need to clarify the scope of this.
