Seconds in voice 2 flip to wrong side of stem

Steps to reproduce bug
1. Open attached file, "Seconds in voice 2.mscz"
2. Press "N" to begin note entry
3. Click to add a note to measure 1, beat 1

Expected behavior: The chord in voice 2 should stay the same (E and B on the right hand side of the staff, A on the left hand side)

Actual behavior: The chord in voice 2 changes its appearance (B and A move to the opposite, incorrect sides of the stem)

Overall rule: The note heads of seconds should touch each other on the diagonal. When the note heads flip to the opposite side they are no longer touching at the diagonal.

MuseScore version: 1.0 stable and r. 3997 nightly build

(Operating System: Windows 7)

first reported by ansonwun: http://musescore.org/en/node/9130