Unable to sort using "Ordering" menu in admin

I am trying to update the order of my site’s pages through the admin, but I am unable to use the “Ordering” option under Pages > [individual page] > Advanced > Ordering. In this case, it’s technically an item/blog item.

I drag the page to the bottom of the list and click Save, but the list reverts to the original when it refreshes.

I’m currently running Grav v1.7.5 & Admin v1.10.3, although this was happening before I upgraded Grav (I think I was on 1.7 or 1.7.3 before today). My file permissions are set to the default Grav settings—755 for folders and 644 for files. I tried setting the folder permissions to 775 to see if maybe it was a permissions issue, but that didn’t change anything.

The only way I’ve been able to get this working is to physically rename the folder via FTP. Which I can do for the short-term, but it’s not exactly ideal.