A number of Canon 1D X Mark III owners have reported issues with Canon’s flagship DSLR, wherein the camera appears to lock up and fall asleep while shooting in continuous mode.

First reported nearly three weeks ago in the DPReview forums, users have noticed their 1D X Mark III cameras seizing up after a few shots, making the camera unusable for a few seconds until it appears to reset.
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https://www.dpreview.com/news/3071838969/several-canon-1d-x-mark-iii-are-reporting-issues-with-the-ovf-freezing-in-burst-mode