Yeah, for me I always took ROTJ as being like a month after ESB. After all, Luke says he's going to meet Lando on Tatooine, and Lando is already on his way it seems, so I assumed that Luke left a couple days later while Lando infiltrated the palace.

But by official timeline, its a year. Never got that. It makes even less sense that Luke never went back to Dagobah either. Clearly it doesn't take place the next day, because Luke has matured more, he has a new Jedi outfit, continued training on his own, built a lightsaber, and Leia took the time to get a bounty hunter outfit while Lando somehow got a job as a palace guard. Its more than just a week after. But a year??