On panics, monitoring sometimes outputs crap. See if it's related to baud rate.
NodeMCU serial interface uses 9600 baud at boot time. To increase the speed after booting, issue uart.setup(0,115200,8,0,1,1) (ESPlorer will do this automatically when changing the speed in the dropdown list).
If the device panics and resets at any time, errors will be written to the serial interface at 115200 bps.
On panics, monitoring sometimes outputs crap. See if it's related to baud rate.