Matching the filename to the title using Tag - Filename inserts a space at the beginning of the new filename.
I have been using it extensively to eliminate unwanted information in the filename thus keeping the filename shorter. It goes unnoticed unless compared to a normal filename.
Even if the filename initially = title, the operation adds a space
A consequence of this is that the alphabetical list of filenames is incorrect and disordered.
Correction will require the use of a programme such as Bulk Rename Utility