Lost my registration

After doing a backup of my entire internal hard drive to an external hard drive DA no longer has my reigistration code. (I have re-entered it and it is working.)

Would the backup cause such a loss? If so, will that require I reenter the number everytime I do a backup?

I’ve made bootable backups of my entire drive including, obviously, my Home directory, which contains the registration information (a .plist file).

Restoring such a backup retains registration information. I haven’t encountered any problems.