Hi,
The most recent update added a new feature to the Arena in the DoR DLC, where if you have bought all items in the Arena shop, the Valkyrie will continue to stock materials instead such as platinum ingots etc. I logged in today and the Valkyrie no longer sells anything, instead, when I select the shop option she says what she would usually say before the update that "there is nothing for you here".
Maybe it is just me that has this problem, could someone else check on PC to see if they can access the shop in the arena and buy platinum ingots and other materials?