Good morning, Ronald and Sherri, and thank you for both your replies.
In essence, I am reassured that you both, in your different ways, confirm that there is something 'corrupt' here. That was what I was mainly wanting to confirm.
The history is that, in absolute original, the midi file behind this *.not is a professionally-produced one from PG Music's Modern Jazz Pianist application. I am currently doing a lot of editing from this file, and others like it, to produce a 'to see' score which is a good prompt for playing the piece.
As you can imagine, this involves using a wide range of NC's facilities, and I save the *.not file very often, usually with a rolling suffix (a,b,c or 1,2,3 or the number of bar reached). So there has been lots of chance for a glitch to creep in. It'd take a lot of effort, now, to trace back to where this particular detail first went wrong.
The not-quite-transcription edit is a fascinating process in itself, and I am beginning to produce scores that are not exact in every detail, but give me a sufficient, and most importantly, easily-read, prompt to play from. I am also actively making notes of the various techniques I use, and I will write them up for one of the other segments of this forum in the next few weeks.
BTW, Sherri, while we're here: I've only recently become aware of the BIAB plug-in, which I read somewhere on your site is available for limited-time free trial - but I couldn't find the download link. Could you post that, please ?
Ian G.
Wales UK