I recently bought a 93 volvo and had the oil changed and a Mann oil filter was used. Immediately after getting the car I went on a 3 day 1,000 mile trip. When I arrived at my destination I happened to notice that the engine was leaking oil. I checked the oil level and saw that there was almost no oil in the engine. I got under the car and found that the leak was coming from the filter. I checked and the filter was tight. I drained the oil and removed the filter and found that the filter looked as if a machine tool had uniformly milled away two areas of the gasket causing a slow leak. I don't think any damage happened to the engine as the check oil light never came on. Has anyone seen a Mann oil filter with a defective gasket?

Thanks,
Stan