I've owned two Brother laser printers in the past 15 years. I've run into this issue with the newer one: it will just refuse to print at a certain point. However, I was able to find a work-around (probably the same one you found) by typing some magic code I got from a YouTube video into the front panel and then it worked for awhile until I did replace the toner cartridge.

Was quite frustrating but nowhere near as bad of some of the HP stories like this that I read on HN.