I've had a similar problem, tried to remove all the cartridges and put them back several times and had no more problems - but don't know if actually that corrected the problem.
Hi,
don't know much about Canon cartridges, but may be the refilling lifespan of the cartridge is near it's end.
I'd buy another cartridge (new or compatible) and check if the nozzle test would come out the same. The purchase of another cartridge is going to take place anytime soon, so no...