Reportedly the ships were performing STS cargo operation while drifting, they weren’t anchored.
Reuters said: “The Maestro was subsequently barred from using Temryuk port in southern Russia by the owners of its only gas terminal, Maktren-Nafta, two industry sources said, where it had previously loaded liquefied petroleum gas of Russian and Kazakh origin for export to the Middle East”.
Reuters kind of, strayed off fairway here – both ships are/were under sanctions, and it wasn’t the question of Temryuk Port accepting or barring sanctioned tankers, it was a technical question of changing papers in order to hide – at least on papers – sellers and origin of the cargo. It was cargo laundering. Advise Reuters do some digging near Europort, or North Cyprus, or in other places, and find out how sanctioned cargoes from/to sanctioned States surface as clean and legitimate.
Full details here: http://maritimebulletin.net/2019/01/21/mayhem-in-kerch-strait-cargo-ship-on-fire-after-reportedly-russian-air-force-attack-video/