i suspect this is related to the fact that shell of venus is the only item in my wardrobe i have two of.

i would try recreating this with some other junk item to test but it seems the system was changed to only allow one copy of things in the wardrobe (and incidentally, i find that frustrating; i really wish i could have several identical cordials)

every time i switch to a page that legitimately contains both shells of venus, the next page i switch to will have one additional shell of venus inserted at the front. this continues indefinitely.

large gif, give it a minute: (i cut out the incredibly long wait time between pages so the actual gif duration isn't that big, it's just large in dimension)

my real copies of shell of venus are on page 2.