I rebuilt XO to build 7579b with no change. I performed an export and import of the VM and the imported VM functioned normally and displayed the disk in the UI appropriately.

And we are blown away by our wonderful community! Thank you very much, and happy to help you!

@stevezemlicka Thanks for mentioning this and reporting your "mistake" on the forums. I had been banging my head against the wall for a day before finding this post and realising the obvious.