https://topwar.ru/145578-s-chernomorskogo-flota-na-baltijskij-alrosa-idet-sluzhit-na-baltiku.html
Google translate wrote:The Commander-in-Chief of the Russian Navy made a decision to redeploy the submarine "Alrosa" from the Black Sea Fleet to the Baltic Fleet, Izvestiya reports with reference to the military leadership of the Russian Navy.
In the military department this redeployment was explained by the almost complete absence of an underwater fleet in the Baltic and the arrival of new submarines on the Black Sea Fleet. The submarine will be included in the Red Banner Leningrad Naval Base (LenVMB) of the Baltic Fleet. Later, the submarine will be sent for modernization. Earlier, "Alrosa" made the transition to the Baltic, in 2011 she arrived in Kronstadt, where the scheduled repair was.
It should be noted that at present there are only two submarines of the project 877 still built on the Baltic - the Vyborg and the Dmitrov. At the same time, the Vyborg submarine built in 1983 was not modernized for a long time and was not repaired and it is planned to withdraw it from the fleet. "Dmitrov" in the period 2014 - 2018 was under repair in Kronstadt.
With only 2 Kilos in Baltic & not new ones it makes sense.
Also possibly what happened with Alrosa: They went too deep while working up after coming out of that 2011 maintenance, nearly sank the thing.
That would make sense for why its had a long maintenance involving the pipes etc so soon after a major refit in 2011
Question would be how they get it back to the Baltic?
Montreux convention allows it out for repairs as in 2011 but is it in condition to be able to make it to Baltic on its own and if its really poked from the incident then it might not be much use in Baltic either