A friend came to me with a problem he had the other day.
His Canon XF300 was performing beautifully during the indoor part of the shoot, but when moved out into daylight the shot became slightly out of focus.
He told me he had checked the auto and manual switch + settings and was baffled as to why it kept reoccurring.
Interestingly the camera returned to normal function once it was brought back into an interior environment.
Unfortunately I do not have the full details on settings etc but if anyone knows of any possible causes it would be much appreciated.