I got a Demonic Vanity Mirror which is a donation item from the Grave Digger Vending Machine.

Could this be an error?!

It is known to happen, but rarely. At least, that's how it used to be. I don't think that got changed :)

SirWilliam.

This is nothing to worry about. Vending machines rarely give out Donation Items, so just be lucky about this one :)

Alright, thank you for the info :)