That’s because you’re attempting to abuse the feature:
Rollbacks are supposed to be used for “help, I got hacked” types of emergencies, not “oops, I didn’t pay attention when salvaging” player errors:
There’s SEVERE restrictions on it, too. Are you SURE you’re going to be happy with only 500 of every single resource in the game being xferred over, and having your crafting professions reset, and having everything being account bound? Just because you salvaged one single primal squirt’s?