I'm on latest build, fast ring. I did a system reset last night and everything's normal now. Besides getting the "your device is up to date" message when searching for today's build..
Could be, that I have the same problem. Can you opt-out of Insider Preview or switch between fast and slow rings? I can't. The setting is just missing. I didn't do a reset or anything and was before on fast ring and didn't change the setting. I am now on 10565 and can't update. I even looked in the registry under "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsSelfHost\Applicability" and compared it to my settings on my SP3 and everything seems fine.
Okay, now the I got the new build, but the insider build settings are still missing. Nevermind, as long as I get new builds, I am happy