This is one of the weirdest bug that I've observed:
It seems that Mail.app's audio notifications for new mail and sending mail accumulate and play in order of occurrence when I unplug external speakers. Just now it played a series of more than 100 notifications (mostly new mail notification).
It's not big enough that I want to fix it but I just wanted to know if anyone experienced something similar.
It happened on an iMac that was upgraded to OS X Lion from Snow Leopard.
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Best Answer
If this bug is repeatable and happens often you should consider filing a bug with Apple via their, Apple Bug Reporter.