Rust under wheel cover emblems

[PliSsK]

I had the Alpina emblem fall off one of the 18" wheel covers on my 2001 B10 earlier in the year and I cleaned up the central area and stuck a dealer supplied Alpina emblem with the adhesive underside on it. I looked at it now and that particular wheel cover seems to have suffered horrific rusting in that brief period, and now the cap is pushed out on one edge because of rusting underneath, and there is rust bubbling up under the paintwork all around the central area of the wheel cover. All the other wheel covers with the original emblems are fine. Did they change the emblem manufacturing quality or was this just bad luck? Or did I miss out on a preparatory phase in installing the new emblem? I imagine the spongey adhesive back traps water and caused the rusting, as the area they go on to is unpainted. Anyone had anything similar? Cheers.