I have noticed a bug in Admin/Users: if you switch tabs (Active, New, Suspended) quickly, you may end up with list of users populated from previous tab. I noticed this when I was switching from Active to Staged and was confused to find whole user list (active) on Staged list (with Staged users header).
BTW, I also find Groups tab annoying, as it does not have same navigation as other tabs: when you select it, you loose navigation and need to go back or restart from top. Groups is also broken on top menu - same behaviour.