The Canon C300 Mark II appears to have a firmware bug. This will need a fix from Canon if the C300 Mark II is to be completely bullet-proof on a shoot.
Highlights burn to black in certain situations (as with car headlights or the sun).
Canon C300 Mark II suffers black spot issue
[youtube]https://www.youtube.com/watch?v=tTQ5uq6PyUg[/youtube]