I setup a 5-stop, 2EV bracket to test (having had problems with this before, seeing multiple identical exposures as someone else noticed).
Went into Info to see what was up, and saw this:
Notice the ev -4, showing 1/8000 @ ISO 4000.
This is technically correct (it is -4, at least it looked like it), but is absolutely the wrong choice - it should have been 1/1250 at ISO 640. The resulting image was really grainy, as you would expect at ISO 4000.
Now that I have seen this I can manually correct, but is there a fix in the works?