I was out yesterday and it looked like my drive-side BB had come loose. Just stripped it and somehow the BB cup has lost the majority of its threads. As per the picture (one on the right) 3/4's of it has lost just over 0.5mm diameter.
Hope Ceramic BB, nearly 4 years old and done an awful lot of k's (probably 10,000). I guess luckily its on a Ti frame, so doesn't seem to have affected the BB threads.
Well maintained, and stripped/cleaned often.