How often do grandmasters fail to mate soon when mate in five or less is possible? The recent question, How often do grandmasters miss checkmate? , turned out to be a bit broad. This question asks about a simple subset of that one, which I hope can be answered with some precision.
How often do grandmasters miss an opportunity for a mate in five or less? Since it matters little if the exact move sequence is followed,I will allow a slightly longer series of moves to be considered not a miss. Consider it a &quot;miss&quot; if twice as many moves (ten) are played before the win,or if there is no win.
Consider classical, over-the-board games.
Let me count the reasons....
It all depends!
And there is no way  to answer your question exactly.
GMs do not play by your  arbitrary evaluation method. They play to win or possibly to not lose. While their tactics are  usually very good , missing a mate in 5 while winning the game is more important to them.
Depending on how they feel,  how much clock time they have,  whether they fear their might be a killer move by opponent they missed if they tried, they will go with what they see as the clearest win no matter how many moves (unless time pressure requires them to win faster as in a SD game with a long difficult endgame vs somehow winning it faster like that mate in 5).