Maybe the time is right. With Russia flexing its muscle you may never know when it could turn its attention back to Cuba.
I would argue that China doesn't need Russia anymore. That was why there was alignment in the past, neither country could face the US alone.
At this point in time I don't think China needs (or wants) to align with anyone else.
This is my own person opinion, but I get the sense that China wants to expand its sphere of influence, but not in such a directly antagonist way to the US as Russia did.
While the US and Russia saw the entire world as a possible sphere of influence, I get the sense that China (at least for now) has a much more local focus.