Minor cookie issue

Mark, a small issue that has remained across numerous updates (currently on 2.6.0). The Cloud Base setting in cookie prefs is set to ft in my situation. However, after leaving the page for some time when I return it has reset itself to m. Consistent in its reset, usually takes at least a day or more of being away from the page before it happens. Returning to the page on the same day as previously viewed shows the ft setting retained.

http://tiggrweather.net/wxssgauges.php

Thanks.