Got a response from Ubisoft:
"Thank you for your interest. Unfortunately, Technical Support has no information available on this subject at this time."
Take it as you will, but if they had actually made a 1.3 patch, I'm sure they'd have been willing to say so, instead of say they don't know anything about it.
Unfortunately, even with the 1.3 patch, every time I've tried to beat the game it eventually stops recognizing quest completion, and I'm unable to continue. Still, might give it another go sometime.