I ended up deleting Christian "Christina" Main after copying her details to Word and re-entered her into the tree. She linked up without an issue to John McKenzie, this (now just plain old John McKenzie).
I think we have an issue here that needs to be addressed. I have been with you for a few years now...never before ran into this problem.
We were going to look at your issue before you fixed it. Please let us know if this happens again and we will check it.