The biggest but not only example: https://en.wikipedia.org/wiki/Tom_Mueller (yes, lots of subcontractors involved, however, Nasa paid, with a bonus percentage provided by the US military)
Note that Mueller gives the payment situation at TRW, and the fact that he "wasn't appreciated" as a direct reason to go to SpaceX.
What did you think happened? Does anyone actually believe Musk did the technical design for that engine, just because he claims so? Or I should say he constantly claims it, staying slightly away from direct claims to avoid getting caught in lies (well ... getting caught AGAIN).
These people and bots have no idea what they are talking about. They’re parrots.