After cleaning and lubricating my 9 speed KMC chain, I checked the wear and to my surprise the checker shown 0.5%. I moved it further and the checker shown almost no wear. Trying to figure out what I am doing and how that can be, I noticed that when measuring over the missing/quick link, the indicated wear is larger. I thought it must be the missing/quick prematurely worn out. So I bought a few new, two KMC and two SRAM 9 speed links. Again, to my surprise, when measuring over the link the wear is 0.5%, anywhere else over the chain is minimal. It happens no matter what missing/quick link I use. Even measuring from the one side of the missing/quick link and away, there is no wear. It is as if that link itself is a bit longer than the others of the chain. No skipping, no strange noises, just that weird chain wear measurements.
What am I doing wrong, what is going on, how can that be?