Yeah its strange, never seen that happen either. Like I say I cleaned shortly before it happened. Must have gotten some oil or something got stuck in it. Not sure, I don't oil any of those parts, maybe a drip got in there. I found the take down tab, it looked fine. Spring didn't break, it was still under tension, It really flew.

I'm a little disappointed I can find a parts list for the SD, its been out for a few years.