Wrong pitch displayed when copying and pasting between instruments of different transpositions

Windows 7, GIT commit: 2bf563b

1) new score for flute and Bb clarinet, key of "C"
2) enter a "C" into the flute part
3) turn concert pitch *on*
4) copy and paste the measure containing the "C" into the clarinet part
5) verify pitch displays and plays back as "C" - the correct result
6) turn concert pitch back *off*

Expected result: clarinet displays "D"
Actual result: clarinet displays "C" (with an explicit natural sign because of the key signature)

Playback is still correct.

I discovered this attempting to recreate the steps that led to the score in #25570: notes displayed differently than played, which appears to my eyes to have its tpc & tpc2 values out of whack (not that I fully understand how they are supposed to work). Maybe copy and paste is how that happened, maybe not, but it's definitely a problem.

I marked this critical since it is a form of data corruption, and it's especially insidious because you don't discover the problem until you turn concert pitch off.