(GAMEPLAY) Stalker Blade Cinderhulk is avaliable to purchase without Smite

I am not sure what made this bug trigger, but basically.

I was playing Nasus and was almost full build. I was checking the store while i waited to respawn and noticed that not only were the Jungle items avaliable to purchase, so was Stalker's Blade with Cinderhulk (I had Bami's Cinder at the time).

I get curious and pressed to purchase. Then i notice that my health didnt change at all. I shrug it off since i was going to undo the purchase anyway, but to my shock, the undo button wasnt working anymore!

Once i respawned, the Cinderhulk actually disapeared from my inventory, with my Bami's Cinder. This caused me to lose the item itself and around 1200 gold.

But yeah, i have no idea how this triggered. I didnt have any space for extra items at that point, had a Bami's and was respawning, but i am unsure which of these factors triggered the bug.