FIDE Rules:
4.3 Except as provided in ArLcle 4.2, if the player having the move touches on the chessboard, with the intenLon of moving or capturing:
4.3.1 one or more of his/her own pieces, he/she must move the first piece touched that can be moved.
4.7 When, as a legal move or part of a legal move, a piece has been released on a square, it cannot be moved to another square on this move.
Pragganda moved the piece that he touched. So no violation of 4.3. He did not release the knight on h4. So no violation of 4.7. He did release the knight on its original square, but that's not a legal move, so 4.7 doesn't apply to that. I see no violation of the rules.
Recently, I watched a YouTube video on the recently concluded Grand Chess Prix.
Here, I watched GM Praggnanda face off against GM Deac-Bogdan in an elite chess tournament. Let's keep in mind that both players are doing extremely well at this point. White eventually won the game, but I believe this result should have been the opposite. Before I explain to you what happened, it is imperative for us to look into what the touch move is.
As defined per Arbiter Handbook: 4.8 A player forfeits his right to claim against his opponent’s violation of Articles
4.1 – 4.7 once the player touches a piece with the intention of moving or
capturing it
In other words, it emphasizes that once a player touches a piece with the intent of moving it (as the White GM did), they are bound by that move, assuming it is legal.
Prag vs Bogdan 3:46
At 3:46, (3 minutes, 46 seconds of the video,) Pragganda physically moves his knight to h4, (a blunder that loses a piece instantly), which would've instantly lost the game had he played it. His opponent (Bogdan-Deac) is away from the board.
He doesn't release the piece from his hand, yet he physically moves the piece over the board and switches his move mid-way. This automatically is an indecent act at best, and at worst, a violation of the fair rules of tournament play.
When White moved their knight physically to h4, they signified that they were willing to play that move. The arbiter handbook emphasizes that once a player has touched a piece while moving it, they are bound to make that move, assuming it is legal.
Did Pragganda make that move mid-way? Was the move legal?
All the answers to the above are yes.