This is interesting actually. See how Elon took the higher ground in the handshake. That shows dominance. Trump countered his dominance by putting his hand on top of Elon's. It the oldest trick in the book. It shows Elon, no you don't! If you look at the other Freemason handshake neither took advantage of the other so the highest ranked puts his hand on top to show dominance.
Probably nothing. Love and Light