Yes, it is the Russians trying to provoke the USA. The reason Cuba is allowing this in their port is that they want the USA to open up to Cuba. Obama tried to ease tensions between the two countries, but Trump shut everything down. On the part of the Russians it is merely a show of their military strength, which is quit weak at this point. They could not even send this sub anywhere near the Ukraine as an American/NATO missile might take it out. The Russian military is in tatters, the Russian economy is in bad shape. Putin has spent away the Russian economy and military budget for decades. The sub showing up in Cuba is merely a show of force. Cuba will use this opportunity to mend diplomatic relations with the USA and make things better to their own people.