i dont think a gm played that
Shortest GM game
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That game is usually credited as being Gibaud vs Lazard, from 1924. While both of those people were masters, neither was a GM.
Moreover, the game appears to not even be real.

As stated above, the Gibeau vs Lazard game's authenticity is questionable; also there were no GM or IM titles in 1924.
The shortest decisive international tournament game that was decided by the position on the board (as opposed to a forfeit or resignation made as a protest, like the second game of the Fischer - Spassky match) was probably Dordevic - Kovacevic, Bela Crkva 1984:
… and who could forget GM Anand's 6-move disaster against GM Zapata at Biel in 1988?
So this last game (Zapata vs Anand, Biel 1988) might be the record holder for GM vs GM decisive games.
Seriously. So much poor play in 4 moves. Someone find this game in the database.