I found a really minor but disrupting and inconsistent glitch in the Color Guide panel.
Here is the help file excerpt and read it carefully (Illustrator Help | Color groups (harmonies))
Show Tints/Shades Adds black to variations on the left and white to variations on the right
Show Warm/Cool Adds red to variations on the left and blue to variations on the right
Show Vivid/Muted Decreases the saturation toward gray in variations on the left and increases saturation toward gray in variations on the right
Where is the issue:
For the first two variations (Tints/Shades and Warm/Cool), the Tints and the Warm are consistent with the interface controls in the panel. Tint precedes Shades and it is on the left side of the panel while Shades is on the right part of the panel. This is also correct with the help file as it explains color variations, adding black or red to the base color.
However, for the Vivid/Muted, the label in the panel's context menu is the other way around. Depicting the interface it should be: Muted/Vivid to fully reflect the layout of the interface controls in the panel.
Here are the screenshots:
