Usually when the rename dialog is opened, both "New name" and "Old name" fields are set to the name of the first of the files selected for renaming. If you then click or select in the preview list to edit macro, the "Old name" and "New name" fields both change automatically to "*", so that the macro will apply to all files, a handy time-saver.
However, when the first file to be renamed has a curly brace "{" in its name, clicking in the preview list to edit macro, the "Old name" and "New name" fields do not get automatically changed to asterisk as normal.
This happens when the first file name contains a "{", whether or not the rest of them do, however it does not with a closing curly bracket "}".
I thought maybe the dialog assumes some regex is being attempted, but this behaviour is not present with carets ^, square brackets [, or parentheses (, so I'm not sure why, or if it is intentional.
It's caught me out a few times where i'd go to edit the file names in the preview list, double tap enter, and nothing actually got renamed. A slight annoyance at most, but strange, no?
Here's a few screenshots of the rename dialog with different sets of file names, after clicking in the preview list: DOpus strange edge case bug(?) - Album on Imgur