I have seen this bug on different sites on different servers, it is an issue with the dynamic sizing of the table td that holds the menu items like status, add items (the + icon), etc. The idea is that the width of the table td will change if items are added to the menu. However, if one wishes to increase the font size for the menu (and the CSS for the submenu bar is tied to this as well, so increasing the font size for the submenu increases the font size for the member menu bar), the table td width does not get resized properly to handle the increased space that increasing the font size results in. Therefore, the content will wrap resulting in the member menu bar doubling in height. On one site with different templates, I have seen the size calculated correctly when switching the template. However, the issue returns as one moves through the size with the member menu bar doubling in height due to the items having to wrap.
It would be nice if the community could help me in finding a solution to this bug.