Cannot move page with children. Page title becomes blank and move fails.

I am trying to move a page and its children.

I go to the Edit tab and and click on EDIT near the current Location.

I select my target space from the Space dropdown and type in Home for the Parent Page (there is a Home page).

I click the move children checkbox.

I click on Save...and then I get the Edit tab returned with an error saying that "You must enter a title." My selections for moving the page have been reset, and the title has indeed been emptied even though I have never touched that value.

I can then put the old title back in, again indicate the move I want to make and...new error: it thinks someone else has also been editing the page and asks if I want to overwrite:

You were editing an outdated version of this page. Another user has updated this page before you. Your changes against the now updated version is shown below. Please decide whether your changes should overwrite it or you wish to discard your changes.

I click overwrite and again "You must enter a title."