EA and DICE did the same thing with BFV in 2018, talking up how accurate the game was going to be when it couldn't be any clearer it wasn't very accurate, and that did not end well. That was also back when there was minor pushback against those things compared to now.
If I were Ubi, I'd either come clean that accuracy was not key to the games direction, or take the time to make AC Shadows much more accurate. Problem now however, is if they do take the time with a delay, they need to make sure it's insanely accurate, because people will go through that game with a fine tooth comb and will blow every inaccuracy out of proportion.