Somehow I cannot recreate this bug though. I tried but apparently cash shop purchase on steam is steam-account bind, meaning that no matter what. The reddit post also clearly state that it is not an exploit so I gave it a try.
-Create an character in NA
-Create an char in DE
-Create an char in IT
(All chars are in same steam account)
-Open shop in DE. Shift Tab and change server Log in to NA
- Shift tab in NA to open the shop. Buy items
-> Gets items in NA.
-Shift tab again
-Change to IT
-Open premium shop.
->Every item in shop says limit reach.
And apparently you can buy from one steam account and send to another.
Correct me if I missed any step