OK, there could be a lot of reasons for that. Would need the log to try to narrow it down.
What happened between these two states?
That would be in the category of lightning striking twice. The ESP has a very very very small window of exposure when loading new firmware. Basically, the new firmware is loaded to an alternate location in the flash and then once it’s verified to be correct using a hash, a single pointer to the new active firmware is altered. Probably takes a few microseconds and should not cause this problem.
That said, you have a bricked IoTaWatt and it needs fixing. You can try reflashing as above, or depending on where you are located, you can send it to OEM or me and we will reflash for you.