Flashing in an energy saving bulb

[singalong]

I recently fitted a Philips 11 watt (60W) Energy Saver lightbulb.
However when it is switched off one of the three glass loops which comprise the element part, flashes on and off around once a second.

I've checked my other energy saver bulbs and this effect is not present.
Can I assume I have a duff bulb and not some effect in this particular make and manufacture.

 

[singalong]

After I posted the above the "similar topics" came up and I found a really good thread from Dec 2006 that gave me all the answers.