I don't think there's any suggestion there was anything wrong with the board, rather it was a tripple sub with the numbers coming off and on meant he needed 186 presses of the + button, as well as checking the numbers are correct and committing the first two changes to memory. Also, the camera wasn't on him all the time so for all we know they could have given him the wrong numbers initially.
The issue is the technology. They are using a board that has been around since only 3 subs could be used and players wore 1 to 16, and certainly weren't wearing number 73. Manually advancing a number from 1 to 73 in increments of just 1 is going to take the best part of 30 seconds.