K5 lens release button broke

Lens release button just fell off while I was taking pictures.. Has anyone else experienced this? The e-clip at the back of the button has fallen off. I have done a thorough check of the button shaft and all the groove edges are still sharp, so I cant see why it should have fallen off.
Just like to know if this is an inherent problem..

It is/was an inherent problem I'm afraid.

In the US I understand some users had replacements sent to them, but most were told it had to go to the main repairers.

A number of users came up with diy repairs.

More on the US forum.