I could understand if Monzo couldn’t/didn’t want to say anything before hand.
But given “how closely” they’ve been working (which both Monzo and CC say), I would have expected some form of communication from Monzo as soon as the email from CC went out, even if that was to say “we’ll be in touch as soon as we can”.
If I’m being a little high maintenance, I’d have expected the Q and A from CC to be arranged immediately to answer the obvious questions.
That’s possibly an expectation based on past experience of Monzo dealing with these kind of things.
They’ve previously set the bar pretty high, so anything short of excellent will look poor.
CC definitely haven’t done anything to make people feel warm and fuzzy, and like you said, Monzo have been harmed by association (although, I don’t actually see many negative feelings towards Monzo on the back of this).