KSP can bend up fine until it reaches the range of an octave, or higher. It does not have this problem going down.
Example: When you reach the top of the pitch bend strip and you are going from a C to an octave up C the top note is significantly flat. A very sharp B.
This has happened on a hardware Yamaha reface CS, and ios apps, Moog model D, Geoshred, and Jordantron.
Before you reach an octave pitch bend, it seems to bend in tune.
Can others test and confirm?