Checkbox disappears after swapping Reference and Dupe photo

[jch1953]

After I click "Make Selected into Reference", the Ref and Dup change places as expected - but the checkbox disappears on the new Dup (which was the large photo that dupeguru makes the Ref photo by default).
See attached jpg - the first pair used the larger photo as Ref.
The second pair is the swapped photos but the new dup (the larger photo) does not have the checkbox.

I do want to Delete the new dup (delete the larger of the 2 photos).

[glubsy]

Post this in the Issues sections, not the Discussions. Also provide Dupeguru version being used.