It seem that both Vladivostok and Sebastopol may have departed Saint-Nazaire 14th/15th January and have (once again) disappeared off the AIS scene. Last time this happened they mysteriously reappeared many miles inland as if someone was playing silly be***rs with the AIS beacons, so this apparent movement may be another red herring.
Or they could now be doing a road test with the new owners, who presumably will want to re-name them and have apparently already signed for some Ka-52Ks. Reported completion of the ship deal is mid-2016.
Ka-52K Katran Helicopter - Naval Technology