Move that file out of the trash, then try to rename the file. Move back to trash, empty the trash.
Try booting into safe boot mode, then try moving the file to trash, and empty the trash - Restart your Mac.
Or - move it out the trash (back into the directory for your TM backups), and let the backup finish (although, after moving to the trash, the backup may not be good now)
Turn OFF Time Machine (UNCHECK the box Back Up Automatically in TM pref pane)
Restart your Mac.
Delete the file.
Try to rename the file. If your system doesn't allow the rename,
turn off SIP, then try the rename.