Sleep mode

Every time I hit the start/stop button and then press the back button the watch enters into sleep mode. I just bought it this week and I’m on the latest software 11.21. I saw in one other forum for the Enduro, someone had the same issue and they were advised to update the software. Not sure if that would help in my case. Help! Thanks! 

UPDATE: I found the issue I’m embarrassed to say my sleep mode settings were from 12:00pm-8:00am. Sweat smile woops