Every response I've gotten from support on this for the last several months is "Yeah, we had a problem but it's fixed now...", so I've rigged up what I consider a pretty good workaround.
I've added two web endpoints to each of my smartapps whose schedulers are important to me.
The first checks the time the last scheduled job ran (updated in state at each run) against the current time. If it's been long enough to declare the scheduler dead, it returns "FAIL", otherwise "FIRING" along with the name of the app and the last time the scheduler ran.
The second simply calls my method that creates the schedules.
This alone makes it easy enough to just bookmark the URLs with all of the auth tokens so it's a one-click operation to check on the scheduler and another click to restart it via my browser, but we're talking about home automation, and that's not very automatic.
This is the part of the post where I go overboard, so feel free to tune out at this point. =)
I'm a network engineer by trade, and that involves monitoring things. My current free weapon of choice is Icinga. Using this, I can have it watch each of my "stamp" URLs. If it sees "FIRING" on the page, it does nothing. If it sees "FAIL", it hits the reschedule URL. Automation!
Now I just need something to monitor my monitoring...