I recognize for a few days, if I change the content of an id3-tag, the old one ist not removed but the new one just added (using Version: 7.4 - r2751 at this moment)

e.g.:
I recognize the misspelled "John Lenon" in the artist tag and change it into "John Lennon". After an "update scan" SC shows "John Lenon; John Lennon" as an artist (I use the ";" as a seperator), although the id3 tag now only is "John Lennon" now. The same happens with entries in the "comment"-field - if I change or delete them, the old entry still is visible, the new one is added with a ";" in front of it. 

If I do a "full rescan" the problem is solved, but I don't wanna do a full rescan every time I correct a spelling mistake.