Is this engine knock ?

4 speed.
I will try to duplicate and video

This occured while setting my curve . I figured I might have had too much advance in under 2000 rpms . I now have my digital curve set .
If its detonation I can tune it out... but if its mechanical I have an issue.
You would think a guy that has been working on engines for 40 years would be familiar with knock/detonation ..lol