hello and welcome to the forum,
never heard of rclone having the ability to create .tar files.
and
never heard of rclone copy modifying the source files
without the debug log, how do you know, as a fact, that it is rclone doing that?
can you post it or the relevant parts that show rclone is modifying the source and creating .tar files?
and here on the forum, i do remember a post i contributed to about .tar files
Can rclone tar files off a directory for a copy in flight