Screen time out not working

has anyone run across this issue when you set a specific time out, the screen dims after the specified time but does not lock, it stays on?
my phone was working just fine, stock not rooted, took the latest update and after that i've been having nothing but weird issues, the other day the notification area at the top was not working, i had to basically check every app, messages etc manually to see updates, had to factory reset the damn thing, now this screen issue, the phones is only 1 month old.
any input?

thanks