Placed the cursor at the end of the top file name.
Then pressed and held Backspace.
Till it reached the p in 720p
All the rest of the file names had extra characters after the p in 720p in this case space e but sometimes more.
I'm not sure what is happening there, and it does not seem to happen for me so far. Could there have been something left-over from previous renames, or extra spaces in the names originally?
The "macro operation" field showing "L42-3/L32-9/L19-12" indicates three separate ranges are being removed from the files, which should not happen if you just click on a point and hold backspace.
By the way I am using Windows 10 Pro Insider Preview Build 14361.re_release.16063-1700.
I tried 5 or 6 time and it happened each time.
I have done a reboot and tried again and it is not happening now.