Moving a page to rename it forgets new name

Using AEM 6.4.6.0, we are consistently seeing what looks like a UI bug when trying to rename a page.

Replication steps:

- select a page and click 'Move' 

- type a new name in the 'Page name after move' box

- press 'Next' to navigate to the next stage of the Move workflow

- select the existing parent folder of the page being moved as the destination

- 'Move' button is now greyed-out (expect it to be enabled at this point)

Workaround:

- after the steps above, click 'Back' (instead of the greyed-out 'Move')

- note that the text in both 'name' boxes has reverted to its current value

- rename the page a second time

- click 'Next' and select the parent folder

- this time, the 'Move' button is available and clicking it results in the page being renamed

My hunch is that the UI is somehow not saving the edits we make to the Name text box on the first page of the workflow, and so when we try and move it to its own folder, it refuses because it looks like we're trying to replace a page with an identical page. When we go back and add the name for a second time, it somehow remembers it this time and can therefore move/rename it within the same folder.

Any ideas what might be causing this and whether there is a more permanent workaround available?

Thanks