Wow.
I used the "Clear" button in the IPTC editor dialog, "OKed", then made a dot in a random field and clicked "OK".
And got this. Same frame. I'll upload the image file if it isn't too big.
Does it mean something that the "City" globe icon in the Reverse Geocode dialog (called from Tools>Reverse Geocode) has a blue glow around it? And yes, "Never overwrite" is unchecked.