I usually use tmutil to restore TM ownership after doing a manual user account restore or after migrating to a new computer. Connect the TM back-up drive. Drag the first folder inside Backups.backupdb after you type "sudo tmutil inheritbackup " in terminal app to supply the path which usually is the Macintosh shared name.
sudo tmutil inheritbackup
Follow that with associating the last TM back-up made. Locate your TM volume then set finder view as list. Open BackupsOpen the first folder inside "Backups.backupdb and the 2nd to last folderbackupdb", shown asinside should be a list, of folders with TM back-up dates in their names. The 2nd to last folder should be the last TM back-up (last folder is actually "Latest" alias). Inside thethat folder should be the name of the volume which is normally "Macintosh HD" or whatever name if it's renamed to something else. Drag that folder below after you type "sudo tmutil associatedisk -a / " to supply the path.
sudo tmutil associatedisk -a /
The best time to use this is before you attempt to use TM after setting-up your account on the replacement Mac or right after logging in after migration. I'm not sure if this will work since you already made manual permissions settings on the time machine back-up folders but it's worth a shot.
Good luck!