I've seen this too, it happened two times that I can remember:
1) I saw both the light bulb notification in the notification area after installing updates which told me to restart my computer due to a kernel update, and the notification inside firefox telling me to restart firefox due to a firefox. I chose the "restart computer" option and when I finished restarting firefox still told me it needed to restart. This one seemed to go away on it's own, I can't remember if firefox told me more than once.
2) One time I installed firefox updates with my user account, and when another user logged in later firefox told that person it needed to restart over and over even though firefox wasn't even running in their account when I installed the updates. This person, by the way, also sees the "Know Your Rights" bar every time firefox starts, as well. So it goes "Know Your Rights" -> Close -> "Restart firefox" -> Close -> "Restart firefox" -> Close... etc.
I agree with what Patrick said with regards to this: "(3) The popup has a close button even though it will reopen after you close it (and remain open in other tabs) This is likely to lead to user frustration."
Why have a close button if it doesn't really close?
I've seen this too, it happened two times that I can remember:
1) I saw both the light bulb notification in the notification area after installing updates which told me to restart my computer due to a kernel update, and the notification inside firefox telling me to restart firefox due to a firefox. I chose the "restart computer" option and when I finished restarting firefox still told me it needed to restart. This one seemed to go away on it's own, I can't remember if firefox told me more than once.
2) One time I installed firefox updates with my user account, and when another user logged in later firefox told that person it needed to restart over and over even though firefox wasn't even running in their account when I installed the updates. This person, by the way, also sees the "Know Your Rights" bar every time firefox starts, as well. So it goes "Know Your Rights" -> Close -> "Restart firefox" -> Close -> "Restart firefox" -> Close... etc.
I agree with what Patrick said with regards to this: "(3) The popup has a close button even though it will reopen after you close it (and remain open in other tabs) This is likely to lead to user frustration."
Why have a close button if it doesn't really close?