Pretty clearly the UK government made the agreement in bad faith. The fallback position that it follows if there was no agreed free trade agreement was clearly understood by everyone.

"Under duress" rather than "In bad faith". Despite Article 50 clearly stating that "Nothing can be agreed until everything is agreed" (wording not checked, but the meaning is there). EU negotiators refused to even start discussing trade terms without an agreed payout, and other restrictions. That is what became the "Withdrawal agreement". Now that the EU (or at least Mr. Michel Barnier) are refusing to discuss trade unless we first give way on fisheries and government aid, we can see the same happening again. Article 50 (part of an international agreement) is clearly being ignored by the EU. Fortunately Boris Johnson is willing to fight fire with fire.

From the above it should be clear that I don't believe that the EU can claim the moral high ground when it comes to keeping aligned with international treaties.