They've traced the cause of the flaws to their sensor supplier's test routines, which missed the problem and caused 95% of the latest batch of sensors to be faulty.
If you want to read the full explanation from Grant Petty, BMD's CEO, it's here.
Just an observation: this is the way to handle PR about delays! Credit to BMD for being so transparent - and it's obviously in their interest because it shows that the problem is not with the camera design, but the manufacturing process. So many in the industry are waiting for this camera - and to see how it performs in the real world - that this type of delay can cause jitters. By handling it like this, from the comments on their forum at least - it looks like they've managed to avoid that.
We'll be testing the BMD Cinema Camera as soon as we can get out hands on one.