Crash on transpose of score containing courtesy accidental

Ubuntu Studio 14.04, GIT commit: c1725a2

1) new score, flute, C major
2) add note "F" to first measure
3) add explicit natural sign to note
4) Select All
5) Notes / Transpose
6) transpose by key to "F"
7) OK

Result: crash

I'm not certain the courtesy accidental is the trigger, but that's the best I could come up with after some trial and error, simplifying from Promenade. And then I see that the selection shows as consisting of a single accidental rather than the range. Interestingly, though my steps above *don't* crash if you transpose to G instead of F. I think maybe it only crashes if the transposition requires the accidental to change from natural to flat or otherwise change type. But that's just a guess.