I had this symptom. I use Linux and with my esp32-Wrover-kit v3 connected via the usb connector the 'ls /dev/tty*' command shows two ports - /dev/ttyUSB0 and /dev/ttyUSB1. I had to set up the menuconfig to use /dev/ttyUSB1 in the 'serial flasher config'. Don't know if this will help you at all.

If it is still of interest, I have run the code on an esp32-Wrover-kit v3 bought only a couple of days ago and it worked fine - red, green, blue in sequence. Just one other thing, on the comment re using transistors to drive the leds, I think I saw something recently that said the GPIO pins can not ...