Note: It is possible that Ukrainians served on the Moskva at some point and knew this info.
It was apparently built in Ukraine, they definitely knew the weaknesses
Ukranians built Moskva, they still have an incomplete sister ship in Mariopol (check for yourself on Goggle maps).
I saw one pic in an article that showed the ship smoking from the starboard side by the forward 130mm gun mount. (treat the rest of this paragraph as reasonable speculation) She may have been struck from ahead. From dead ahead the missle director (TOP DOME) for her SA-N-6 (S-300) would be obstructed by her own superstructure in low level attacks. Her SA-N-4 launchers (mounted aft) would be similarly obstructed. this would leave 2 AK-630 mounts as her only defense, and these may be obstructed by her own bow.
The real kicker here is that the Moskva was all the area defence SAM systems afloat in the Black Sea Fleet, so closing the coast is now a real bad idea.