I was being facetious - however my guess is that someone the OP has spoken to in the city thinks that is a legitimate option...
Now, for a helpful answer - pass it and move on. You are a new B.O., and you cannot be held responsible for the work of your predecessors. Save your willingness to stand firm for a situation that happened during your employment. The homeowner did not know anything about that requirement, and it wasn't called out by anybody ahead of time.
The time to act was before, now is too late. Clearly document who dropped the ball, clearly inform everyone involved that a violation exists and that you will not pursue it from an enforcement standpoint because it was caused by the failures of a previous administration, and call it a day.
Edit: I re-read the OP, and if the architect was notified in writing, I think you should stand strong. Please disregard the previous answer, I had assumed no one had been informed at all.