You might check your tank to make sure there aren’t any clouded areas or bits of resin floating around. Oftentimes, this can be from particulate in the tank scattering the laser. Filtering the tank will help to ensure that there isn’t any rogue cured resin floating around.
Clouded areas are damages/micro cracks in the PDMS. Try to avoid the area. If the clouding becomes too severe, you have to replace the tank. When your tank is too clouded, you see this back in the surface roughness and print accuracy of the part(very small features don’t print nicely while it is no problem with a new tank).
Echoing what @fantasy2 said. Clouded areas of the PDMS unfortunately cannot be cleaned and should be avoided. We find that most users can comfortably go through 2L of resin before having to replace a tank. If you evenly distribute your parts on the build platform, tank life can be extended even beyond that.