Crafting similiar items

For example, I had [Workshop Cat] craft Thin Ring x4. Mail indicated that [Workshop Cat] “I’ve finished upgrading Thin Ring” twice–back to back. However, there was only one I was able to receive and the second automatically showed as “Received” without any action on my part (I’m a two day newbie way playing around for a +2 item, so if there is a guide–I guarantee I haven’t read it yet).

However, this has also happened when I tried to obtain two Belt +1s and two +1 Long Sword(Fire). I’m good at breaking things but is the +1 the highest an item can get?