Manually add order doesn’t work – cannot change user

I have a problem where in Learnpress>Orders>Edit order, I click the link to change the customer from the Guest default, the popup opens for me to search for a user, and when I find the user I want to assign the order to it seems to work, but then when I click on the right to “Update” the record, it then reverts back to the Guest user?

How can I assign the order to the user of my choice? I also tried selecting from the drop down above the “Update” button and selected the only option “Trigger action of current order status”, then clicked update and still the user account for the order reverts to “Guest”.

Please help – this is a pretty critical issue!