This pattern never had a problem with holes because there was an SSK joining each new triangle to the old when I turned. This worked well, but there is a slight ridge which you can see in the photo. I don't mind this as it looks part of the pattern and the ridge made by the increases at the edge sort of matches it.

I think in other cases you have to twist the working yarn around one more stitch to avoid a hole, but that wasn't necessary here.