MIDI Delete Doubles not working

A new occurrence for me; after a session recording MIDI keyboard, I noticed all notes were doubled. When I highlight the notes I’d like to affect and choose MIDI/Functions/Delete Doubles - nothing happens! Anyone else notice this behavior with Nuendo 7.1?

While there are certain anomalies with that function, it should work.

Are the notes on different midi channels by chance?

Thanks for the reply, Steve. Just one midi channel for all notes, but while recording the inspector showed “All MIDI Inputs” active, and for playback “Any” channel is selected.