I've been working on a few simple projects using some ESP8266 dev boards like the very common NodeMCU 1.0 based on the ESP-12N module. Everything has been mostly fine, and despite some difficulties learning the quirks of the ESP8266 chipset compared to the ATMegas/MSPs/etc, I've been able to achieve the desired outcomes.
However, today, for the second time something quite interesting happened. Without any specific reason, one of the NodeMCUs (currently programmed as a thermometer and connected via MQTT to a broker) simply dropped from the network... and started jamming the surrounding area.
No other device, be a phone, other MCUs or PCs were able to connect to the the networks they were connecting just fine a few minutes before. Even if they saw the network SSID listed, any attempt to connect would result in failure.
By trial-and-error, I unpowered tne of the NodeMCUs (the problematic one) and the next second everything was fine again. Plugged it in, and the network went down.
However, I left it unplugged for about 10 minutes, and tried again, and everything was fine.
It also happened a few weeks ago when experimenting with a second-hand ESP01 module and at the time I attributed the problem to bad programming - flashed something else and it began working again.
Googling around I couldn't find but one cause of this problem, caused by power supply problems (already replaced both the NodeMCU and the power supply, but couldn't reproduce the problem with the old components)
Any hints as for what could be causing this?
Thanks in advance