I don't have an illustration of this and will try to create one tonight, if it's helpful, but it appears that sometimes (and for some unknown reason) I get blotchy renders that appear to be skipped render blocks. The blotches are in the same shape as the pre-GI render and these blotches (raw, tangled, miry messes of not fully rendered image) are accompanied by an error message saying there was an error with something to do with a render command. Wish I could remember the error exactly, but can find it later tonight, if you want it.