Let Me Remind You...

 ... that Soviet Navy was constantly present in Cuba through 1960s to 1980s. Visits have been regular and even one of the classes of my naval academy went on navigation cruise Kronstadt-Cienfuegos-Cartagena in 1970s. Here is one of the missile cruisers of pr. 58 leaving Cuba in 1969. 

It is absolutely normal for the US to react by tracking these ships.
  

Obviously, the class of these ships--both carriers of hypersonic missiles and extremely long range advanced stand-off weapons under present circumstances with the US unleashing a proxy war against Russia is concerning for the US. It takes 3M22 Zircon about 9 minutes to fly to, God forbid, Norfolk if launched anywhere from Bahamas area. 

But I do not take these concerns too seriously because as a former naval professional I totally understand, as do people in the US Navy, it is what is NOT demonstrated by Russia that should be concerning for them and these are Russian Navy's nuclear subs which patrol off both US shores and do it in a fully clandestine manner. Their tasks, whatever they are, are to remain invisible first and foremost. Is Russia making a public point in Cuba? Absolutely, including highly publicized exercises on simulation of missile launches to the ranges beyond 600 kilometers with "autonomous targeting", meaning that targeting is obtained purely through own sensors and helicopter, not from the external targeting such as would be targeting from Liana satellite constellation. Gorshkov's Monolit radar in passive mode can track surface targets up to 450 kilometers. So, we may only speculate how such a long range targeting could be obtained autonomously. 

It is clear that Gorshkov carries latest version of venerable Ka-27, Ka-27M. 

The "M" version of Ka-27 carries new radar and extends surface search capabilities dramatically. So, most likely, it was Ka-27M (operational range 980 kilometers) which could have provided such targeting.