Hi Craig,
I think I actually DID find a bug.
I think it may have to do with 16th notes. Can you try the following?
1. Draw in the 16th notes in the picture below including the velocity changes in the first measure. (keep the velocity consistent in the 2nd measure).
2. Copy the first measure into the clipboard (CTRL+C)
3. Select the the 2nd measure only and choose "Groove Quantize"
4. Make sure Clipboard is the source, the resolution is 1/16, and that velocity is up to 100% in the dialog window, then hit OK.
5. You should see NO velocity changes made to the 2nd measure

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To prove the bug:
1. Draw in the quarter notes in the picture below including the velocity changes in the first measure. (keep the velocity consistent in the 2nd measure).
2. Copy the first measure into the clipboard (CTRL+C)
3. Select the the 2nd measure only and choose "Groove Quantize"
4. Make sure Clipboard is the source, the resolution is 1/16, and that velocity is up to 100% in the dialog window, then hit OK.
5. You should see now see the problem. It works fine except for 16th notes.
Bug?