Brompton owners

I do wonder if this is because you have changed the pedals?
The cheap flexy originals might absorb enough of the stress that would otherwise cause the cranks to fail?

Especially given that you would inevitably put a lot more power through clipless pedals.

Has anyone broken cranks on the original pedals?

BlueQuinn you make a good point - But I only changed the pedals a few months ago. Whilst they are M324s I have never used proper shoes on the Brompton. ( I can't bring myself to wearing MTB style shoes on a Brompton.) I use the platform side with regular shoes. The only reason I swapped the pedals was I got through 3 drive side pedals in like 5 months.

The fact Brompton have changed their cranks again since the 2011 updates seems to imply there have been other incidents like this with those cranks.