This is not really a general windows / robocopy forum but anyway.
It all depends on what was wrong with the file.
If robocopy don't error out because it's corrupted (e.g. physical error on the drive or filesystem) then robocopy will just see it as any other file.
You would need something like a verified checksum and compare the checksum to what you have now to see if data have changed in the file.
/r would just retry to copy the file, so if there is a problem with the drive/filesystem retrying would most likely not help.
You can give it a try of course but if it's broken it's broken.