I've found the culprit. The remanufactured black cartridge was not printing evenly across the page, even it's still has 36% left. (I made a simple test sheet comprising of of black, red, blue and yellow bars across the page.) I changed it with a new genuine HP cartridge, reset the NVRAM and recalibrated print quality, and it's been fine for the last two days.
Apparently when one cartridge is not printing high quality, then alignment fails and print quality calibration can't correct it. Here's a general link about how HP printers align the toners :
