Who knows, there can be many reasons on either side for copying strange calls. The complete callsigns as you read them might give more clues.
So many German special prefixes have been heard in recent years, they are not that special any more and may not even be deemed worth spotting on the DX cluster. A DR25GRENZE station has indeed been active in January on 40 m SSB (one single spot on dxsummit.fi), they might be activated now and then again during 2014. QRZ.com lives from user input - if nobody writes an entry for a station, you won’t find it there. However, QSL cards of German stations with special prefixes are usually sent through the bureau, thus there is little need for an address.