Sure, but according to episode 5 and 6, Yoda must have taught the technique to Obi Wan, possibly in sight of Anikin, since Obi Wan was able to force ghost in both episode 5 TESB, and episode 6 TRoTJ, and Anikin was able to do it at the end of TRoTJ. Therefore any Jedi after the clone wars episode that Yoda learned the ability in, should, theoretically, have been told about the ability by Yoda, because there’s almost no other explanation as to how that ability got spread throughout the Jedi so quickly, when it is clear that it didn’t spread throughout the Sith.