no it has nothing to do with the oil, synthetic oil won't leak out of the filter any more than conventional oil. One drop of oil doesn't sound like much, it could be residue left over from the installation. I say wipe the filter completely clean and inspect it again after a day of driving to see if it re-appears. As long as you didn't over-tighten the filter it shouldn't leak. I usually do mine about 3/4 to 1 turn after the gasket contacts the mating surface, no more and no less than that, and be sure to lube the gasket before hand. One other piece of advice, is always inspect the old filter that you remove to make sure the gasket gets removed with it. A few times I've seen the gasket remain stuck to the mating surface after the filter is removed, then when your install the new filter you end up with two gaskets crushing together and that can cause significant leakage and possible engine damage. | 
