Last night I had an email telling me that the problem had been fixed. I tested out the two examples I had given and they did show the correct relationship.
However, I later found that these were the only two that had been fixed. I still have many, many more showing an incorrect relationship.
I just cannot under how the parent of a great grandparent can suddenly change to being a great grandparent of a great grand uncle. Or a father-in-law of a great grand aunt.
You are certainly correct in saying it happens because some great grandparents have more than one child who is also a great grandparent. None of my ancestors in the first few hundred years display an incorrect relationship.