SilverWook said:

Nice that they are planning ahead, if that's the case.

Lucas did shoot the end of ROTS while filming in Tunisia for AOTC. He chucked that footage, and shot the actors again on ROTS with bluescreen though.

George wanted to have all the Dagobah scenes for ROTJ shot during production on ESB, (to avoid having to rebuild the massive set again) but they just ran out of time.

Here's the latest report. It makes sense they would return to that location in Episode VIII if TFA ends there with Rey and Luke.