If you don’t want to read all the Github thread then Ivan’s (Mr ESP, @igrr) last post is all you need to know.
Are you following these steps?
- upload initial code into module over serial
- power off the module
- power it back on
- perform OTA
The failure to reset after a Serial flash can occur with any sketch at any time and AFAIK there is no known fix at this current time. You will see that the Github thread was started last November and the milestone for the fix just keeps moving on. This bug only affects the FIRST software reset after the serial flash, any subsequent software resets are fine.