Are you positive that the timer itself is running more than once? There is a setting on it called “Completion Behavior” which by default is set to “Stop”, which disables the timer from starting again. You have to switch it to “Reset” for it to be able to play again. Not sure if that’s what you’re dealing with here but figured I’d mention it.
But if found somewhere on this forum that i am not the only one to have this problem, the other person who had this problem added a sleep of 0.2s to make it work… I changed my code to make a timer for the intro (get ready, 5, 4, 3 …) and then the game.