From pics I agree with stress crack from corner. Not ready to blame the installer, as it could be from shrinkage, settling, or the recent storms.
As to repair, as other's have said, epoxy & colorant.
If you want to DIY, I've used white PC-11 and used grout to add color. Tape on both sides and a single edged razor to plane it down before it hardens.
It's easier than siding.
