Comment #2 on issue 3066 by [email protected]: tie in TabStaff (using q) displays one of the unisone notes in a chord
http://code.google.com/p/lilypond/issues/detail?id=3066
If you want to use chord repetitions in music, you should be using \tabChordRepeats to retain the string/finger info. This changes the output indeed; funnily, it makes the empty string repeats appear in the output instead of the fingered ones.
So it is almost the same bug.
