Seemingly unstable GPIO output while executing from RetroPie

[LouF]

I have Python code that instructs a GPIO pin to supply a MOSFET transistor with a signal to turn on/off LED lights. I have problems with the lights not staying on after executing the code via RetroPie (automatically at boot, and manually vie the RetroPie menu). I do not believe it has anything to do with the electronics; the signal seems to be dropped to the output pin.

I have the LEDs fade up with pulse width modulation (PWM) and then I attempt to set the pin to "on" following the ramp-up. It seems to have a problem after PWM. I set the pin HIGH, LOW, 0, 1 -- it just seems to do whatever it wants after the PWM, that is, either on or off whether it was told to be on or off. I've tried putting a pause after the modulation, and I currently have the whole pin re-initiated after the PWM loop (which I don't know why that isn't putting out an error). It seems to work fine from command line (but I have messed with this for so long, that I may not be correct on that). My program logic is that the pin is opened/initialized, faded up with PWM'd, and then set to "on", but something goes regularly wrong.

During boot, the Python code is run from ( /etc/rc.local):
...
python /home/pi/gameltsfade.py &
exit 0

Manually, they can be operated from RetroPie menu ( ~RetroPie/retropiemenu/Game lights ON.sh):
!#/bin/bash

python /home/pi/gameltsfade.py

gameltsfade.py programming
import RPi.GPIO as GPIO # Importing RPi library to use the GPIO pins
from time import sleep # Importing sleep from time library
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD) # set BOARD pin numbering system
GPIO.setup(11, GPIO.OUT) # Declaring pin 11 as output pin

pwm=GPIO.PWM(11,100) # Created a PWM object
pwm.start(0) # Started PWM at 0% duty cycle

for x in range(100): # loop for 200 times
pwm.ChangeDutyCycle(x) # set duty cycle
sleep(0.01) # Delay for 30mS in loop
(#) pwm.stop()
(#) GPIO.setup(11, GPIO.OUT, initial=GPIO.HIGH)
(#) pwm.start(100)
(#) pwm.ChangeDutyCycle(100)
(#) print("end of loop")
(#) sleep(2)
(#) GPIO.output(11, 1)******
sleep(0.5)
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD) # set BOARD pin numbering system
GPIO.setup(11, GPIO.OUT) # Declaring pin 11 as output pin
GPIO.output(11, GPIO.HIGH)
(#) print("set at 1")
(#) sleep(3)

(you can see commented-out troubleshooting lines. As it stands, it functions, although unreliable)

(Note: Commented lines in this copy of the code are in parenthesis so the text does not go to a large size in this post.)

(I also have this manually operable through Kodi add-ons (separate code) with similar results - actually in Kodi, it never stays on (when pulse width modulation is used).

I hope this is an appropriate place for this post.
Comments on the problem are appreciated.