Prowse has been lied to and screwed over by Lucas from day one, so I’m not surprised he was “acting as jerk”. I certainly trust him more than Lucas when it comes to the history of these movies, considering Lucas’ entire version of events has been contradicted by other figures in one way or another over the years. It seems more likely to me that Prowse was banned from LFL events for not sticking to the ‘official story’.
Nobody is claiming Lucas to be a saint.
But Prowse was in hot water the moment he leaked the ESB twist well before the film ever came out. He was also never hired to voice or physically (as in, out of the suit) play Darth Vader, Lucas just said he might be able to; not to mention he was barely in ROTJ and fired before the mask scene was even filmed. This stuff happens all the time, and that’s hardly being "lied to."
Prowse is not some poor innocent victim nasty old Lucasfilm bullied for fun.
Yet he never leaked the ESB twist. This has been proven since. That article came out before ESB had even started filming. The reporter on that article never even got to speak to Prowse at this even where he is supposed to have said this. His source was someone very close to Lucas but he had to use a name for the quote and he used Prowse’s. It was impossible for Dave to have even known that twist, especially when they hadn’t even been given the script at this point and even if he had a copy, it had " obi-wan killed your father" as the twist.
But that isn’t even the article that turned george against Prowse. It was an article in a UK newspaper during the time ROTJ was in production which gave away the fact that Darth Vader was going to die at the end of ROTJ. That again used Dave’s name as the source and George went batshit crazy at him and that’s when it all started. He even refused to invite him to the UK premier because of it. But go watch the doc “I am your Father”. The original reporter is interviewed and he tells how they were getting leaks and that they had to have a name to back up the story so, yet again, used Dave’s name. He NEVER leaked anything to the press.
Even though this is widely-known information, for reliable source you can refer to Making of ESB by Rinzle
Those books aren’t as “reliable” as you may think. People who worked on those movies have stated that they are basically the “Revised history according to George Lucas”.