Hi Kevin,
Thank you for writing to us.
Please let me know where this is happening in your tree, and I will investigate this issue further.
Best Regards,
Esther / MyHeritage Team
Hi Ester,
It happened when I tried to add a sposue to Thomas O'Donnell (b. 1963). I was finally able to add a spouse by adding an "unknown" spouse without name, gender, etc. I then went back and edited in the details. Thanks