When I opened Central today, the tooltip over the first project in Central got shown (after I hovered my mouse over) and subsequently it would get stuck there and other tooltips would show up over it.

Radim said this happened in your demo also, so I think you know this bug. (It seems there is no JIRA yet.)

I tried to replicate this several times, always closing and opening Central, and I was able to replicate every time. You just need to hover your mouse over the items pretty quickly and sooner or later one of the tooltips will get stuck.