I've got a bit to add to this.
I've previously filed a bug report on a problem we had connecting to wifi while doing something with SPIFlash. While reproducing that (on OS 36) I had seen this "wifi failed to initialize" thing once or twice, so they might be related.
Yesterday, some odd data in the backend made me take a look at the logs for a production device. It was running code that we have not previously had these problems with, and still on OS release 34.11. The logs showed the device crashing with this error twice, less than an hour apart, and I believe that I would have seen more had I started the logs earlier. There's not much else in the logs so I don't know if they'll help you diagnose, and I don't know how to reproduce it. We also saw erratic battery voltage readings ranging between 4 and 5 volts over a short period of time (seemingly around the same time as the errors), which might be relevant. I'm not aware of this issue effecting any other devices.
Let me know if you want logs or a device id or anything.