Despite the efforts of Venezuela and Bolivia, the Castro government of Cuba has rejected the invitation to reenter the OAS. This certainly strikes me as no surprise and I think that Human Rights Watch's Jose Miguel Vivanco strikes the right note here:
If I were among the leaders of those nations who had been involved in trying to get Cuba readmitted, I'd certainly feel betrayed. While the true believers (i.e. Bolivia and Venezuela) probably knew this all along and applaud it, one wonders if the others aren't more than a bit peeved.
It's in keeping with the Castro brothers form. When things start to thaw, they make sure the chill comes back.