Samsung has pushed out quite a few updates to the Galaxy Note 5 since its launch, and the latest one seems to have introduced a bug that doesn't let the Do Not Disturb mode turn on as scheduled. I've seen it bug out twice and not turn on at the scheduled time.
This hasn't happened before, and it's possible the latest update introduced the bug. I managed to fix it by manually turning Do Not Disturb on and off and also toggling the ‘Turn on as scheduled' to off and back on again. It's also possible this isn't related to the latest update and could be a general glitch in the software that won't happen again, but it's something that certainly managed to disturb me in the wee hours of the night.
Have you faced a similar issue on your Galaxy Note 5, or even the Galaxy S6 edge+ which shares its software with the Note 5? Let us know if you have by leaving a comment down below.