First: kudos for RTFM and learning that you could batch operations. Honestly, you might have inspired me to do it, too. Isn't it funny that a microwave with a local wifi network and the ability to run JS/Lua/whatever scripts would be exponentially more useful than "smart" features?

I agree, what you are describing is thoroughly bizarre. When you say that it wouldn't start, do you mean that it wouldn't let you hit the start button at all, or that the timer would run out and then nothing would happen?

The only thing I can think to ask from a debugging perspective is whether there's someone in your home who was using a mode last thing before bed that would have set it in an uncertain state?

Heck, even the moisture sensor, or whether someone opens the door on the last second of a cook before a beep could leave some register in an uncertain state.