Blue light filter turns on automatically at sunset, but often doesn't turn off at sunrise I have a manufacturer-unlocked Samsung Galaxy S7 Edge (purchased directly from samsung.com), which came with Marshmallow but has been updated OTA to 7.0 Nougat, and is not rooted.
One new feature Marshmallow brings is the Blue Light Filter, which has options for automatically turning on and off, either according to a schedule you specify, or at night based on your local sunset and sunrise.

I'm using the latter option, and while I've found the filter to reliably turn on every day at sunset, I frequently have to manually turn it off the next day. It's not 100% of the time though, and in fact, on rare occasions, I have woken up before sunrise and been using my phone when the filter suddenly turned off, so I know it is at least capable of working properly. (Note that it has never, to my knowledge, failed to turn on at sunset, regardless of whether I'm using it at that time or not.) I'm speculating that maybe it's failing to turn off if the phone is in deep sleep mode at sunrise. The times of sunset and sunrise are determined based on your location, so an as-yet-unnoticed issue with Location Services could theoretically be a factor as well.

I did a Google search and was able to find informational articles about the feature in general, as well as multiple forum posts from users experiencing problems getting the feature to turn on or work at all, but found no reports of it otherwise working properly, but not automatically turning off.

Am I the only one experiencing this issue? Is it something specific to the S7 Edge, or to Samsung builds in general, or is the same problem known to occur on other devices? And of course, most importantly: How can I get the Blue Light Filter to reliably turn off at sunrise?
It turns out that it seems to be related to the power-saving features on the S7. Apparently at some point, the background process that automatically turns the filter on and off at scheduled times got added to the list of processes to be managed by the power-saving mechanism, after which point, any time my phone was in power-saving mode and had not been used recently, the scheduled toggle of the filter's state would not fire. I'm assuming that was just never the case at sunset, as I'm much more likely to have used my phone recently at sunset than at sunrise.