Needs to be replaced with new gasket not used ones
Idiots trying to save a couple bucks. When I worked at a authorized Puch dealer/motorcycle shop (well not really worked just did a few things here and there and hung out) whenever a bike would come in and needed to head to be removed like for decarbonization or leak we would put a new head gasket on even if it didn't come with the head gasket (some years hi torque cylinders) because unless you got the head in the exact same place on the cylinder where it sat it could leak.
This was especially true if somebody bumped in the head on their bike against something hard like a curb that caused the leak. The shop had very thin head gaskets really didn't change the compression much at all and usually after you got the carbon removed on the exhaust port, pipe, piston and free up the stuck carbonized rings the bike ran much better anyway.
The mechanics at the shop were very good and conscientious with very few callbacks. I learned a lot from them and one of the things was not to reuse old gaskets. Most times they used new nuts and washers too for a perfect torque.
I myself at least flip the head washers to the smooth side so they torque better if new are not available.