The pintle injectors tend to generate droplets after impingement of the fuel and the oxidiser stream and I understand that the droplets will be premixed.
In such a case, even a larger premixed droplet will burn faster than a non-premixed droplet. So, I guess that larger droplets from the injector are acceptable.
Just to verify the idea, I would like to know what is the typical size of droplets in regular engines using pintle injector? (droplet size and velocity of the Merlin engine or Lunar Decent Module would be interesting to compare).