Jaitea said:

ESB was 1980.....ROJ was '83.....um....3years ;)

No, I think it makes sense that Luke returned to Yoda between ESB & ROJ....the way he asks Yoda, "Is Darth Vader my father?" sounds to me like he had asked Yoda before, but now was pressurising him on the subject now that Yoda was on his death bed

Luke says to Artoo when heading towards Dagobah "I have a promise to keep to an old friend". No, this is clearly meant to be his first visit since he left in ESB. They might have spoken over the phone in the last few months though. ;)