Why do my phone settings keep defaulting back to original settings?

[AC Question]

I have a Nexus 5 and it seems a lot of setting options I choose are defaulting back to their original settings consistently. For example, my gmail notifications keep switching back to "off", my display keeps switching back to "portrait view" and now when I lower the ring tone volume to mute, it will turn up by itself again. These are just a few of the issues. Whenever I change the setting, it lasts for a little while and then automatically resets. It seems to be affecting random settings, and over time it happens with more and more of them. I have the latest system update. I thought it might be a glitch, but it was never fixed. Is this a common problem? I tried searching the issue and could find no information.