Activity Startup turns my device on and then back off again

My activity is set to turn on 3 devices, 2 turn on OK but 1 of them turns On and then turns back off again. In my Startup config it should only turn on yet I see the light on the device flash 6 times as if it is getting multiple commands. Maybe the ON button signal is set too long but how can I reduce it, or how do I fix this problem.