Articulations causing issues with MIDI input

When entering notes via MIDI keyboard (in step-time) I will enter dynamics, slurs, and articulations as I go. This is causing an issue where it stops advancing and just stacks the notes onto the same chord.
1) Enter a note via MIDI keyboard
2) Use a keyboard shortcut such as Shift+S for staccato
3) Enter the next note via MIDI keyboard
I am still in Note Input mode and the notehead is still highlighted blue, but instead of advancing as normal it adds the note(s) to the previous one as harmonic intervals/chords.
It doesn't do this consistently, or even most of the time, but about 1 out of 4 times which is frustrating if you're looking at the piano/manuscript and not at the computer screen.