I am on iMac, Big Sur 11.6.1, Finale 27.1.0
First time I see this:
In PDF from score measure looks like this - which is correct:
In the Finale file which produced the PDF it looks like that:
So, I understand that for some reason Finale shows me the notes it actually plays back to make the trill. Never seen this in decades of Finale work. I didn't see these greyed out notes when I was working on the file - but after making a recording they were there. These notes also pop up now in the parts. They are not on a specific layer. I can copy/paste the measure to another file and the notes are still there.
One thing I see is that these notes are on V2 and set to invisible. Getting rid of them is a pain..... At least so far they haven't re-appeared.
Possible explanation: This Finale file was made a few versions back. I used to put the small, bracketed trill notes on V2. But they had been deleted before recording.