That is far from normal. I have never had varnish form on any dipstick ever! I have seen it on other peoples but never on my vechiles or any of the vechiles I have ever taken care of! Something is not right!!! Your combination of oil, driving cycle and OCI are not optimum ! SO you either need to change your driveing habits, change oil more often or step up to a better oil! Mechanicly you could have anissue like a leaking injector, bad thermostat, badly pluged up egr or pcv system etc... It is not normal at all! That is like someone saying it is normal to have fungus or mold growing on your skin or that itis normal to have pluged p arterys!! While both of the above may be more common they we know it is not normal!