SHIFT-<NOTE> adds note to same octave when key signature contains flats
Steps to reproduce:
1. Create a score with a key signature containing flats (e.g. Bb major).
2. Add an Eflat (press E) and press SHIFT-E.
Instead of an octave you get a second Eflat in the same octave.
I did this in the base staff of the following example. (Same for Bflat in m2)
If you add more notes in between the octave (see treble staff in image) or add a note that is not affected by a flat of the key signature, there's no problem.
Marked minor since it can be easily worked around using CTRL-UP.
Using MuseScore release 2.0 on Kubuntu 14.04