[ruonis55]

I'm also interested about the limits and restrictions of Amazon's refund on scan. However, I also believe that a big part of whether it's instant depends on the account.

Even if your account is very aged, you can't get a quick refund on Apple items, GPU's , CPU's. There alll flagged to be checked by the  warehouse.

I am intriqued by this too. Last month I returned 2 separate packages from the same order to amz.de
package 1 = cheap electronic item 30€, legit return, waited about 2 weeks before refund was processed.
package 2 = 2x sporting items, 260€, ftid failed, AR upon scan

I couldn't work out the logic.

Maybe your FTID was not have done properly. They are quite strict on the FTID nowadays. A Lost In Transit would be better.