Notes in Note Velocity are gray when they are muted.
You may have found another bug in Piano Roll.
In the movie, two regions are represented by color, green and purple. I select only a few of the purple notes and mute them. Watch: all control points represented from the purple region appear muted (go gray) in MIDI Draw. In the upper pane of Piano Roll, notes outside of the selection are clearly not muted. When I unmute the selected notes, all Note Velocity points from the region "unmet" (go back to green), though some never were muted in the first place.
This proves that MIDI Draw Note Velocity can falsely represent unmuted notes as muted. In your example you have just a few notes muted. As a diagnostic, you could hit Select All, then unmute (control M), and it'd probably make all Note Velocity points green again. If I'm right, well, we can't fix it, but at least we can be aware.
This post may find a home in the Bug forum, pending Eric's review. Actually, it may already be there, though surprisingly I had not noticed it before.
6-core Mac Mini 2018 with 64 GB and OS 11.3 running Logic 10.6.2, 8-core Mac Pro 2.8 (early 2008) with 16 GB RAM and OS 10.14.1 running Logic 10.4.3, Mac Mini Server mid-2011, Logic Control, Vienna Ensemble Pro (VI and Synchron), Vienna MIR, Ivory