If you look at the mcp_notes_user.html and memberlist_body.html template files, you can see there are {RANK_IMG}, {GROUP_RANK} and {RANK_TITLE} variables.

However, {RANG_IMG} isn't displayed, even if the selected user (for mcp notes) or the selected users group (for memberlist) has a rank image. In addition, {GROUP_RANK} isn't displayed in memberlist, even if the selected users group has a defined (special or not) rank. Finally, {RANK_TITLE} isn't displayed in mcp notes, even if the selected user has a defined (special or not) rank.

I suspect these three variables haven't been defined in PHP files related to MCP notes and memberlist, despite they are included in the related template files.