After wathing html5 video, firefox doesn't quit and consumes 100% CPU

[clutton]

This problem hit my eyes since 24 version of firefox.
I don't have the flash player installed.
And the problem is not always reproducible, it's 1/3 I think.
I can reproduce the problem in safe mode too, so it is not an addon
issue.

top -H:
 PID USERNAME  PRI NICE SIZE RES STATE C TIME  WCPU   COMMAND
 1883 username 102  0 1227M 619M CPU0 0 2:18 100.00% frefox{Media State}

Am I only one who experience this behaviour?
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