Morty Card is one of those items, that won't stay locked, if you use one of the kind in your free inventory. Like I locked 2 and wanted to use a third one, which was in the free inventory. Yet, one of the locked ones got used and the 3rd one remained in my inventory.

This is somewhat of an assumption based on years of using subeta but I believe that anything you do in the inventory uses the oldest copy in your inventory.

So in your case you locked card one and two but left card three unlocked. But when you used a card, it still uses card one because they have the same item ID, and that's why card three was still unlocked. (even though you clicked card three to use, it still counts them as the 'same item' in your inventory.)

Again, a bit of an assumption since I'm not positive how the coding works but I believe ? that's what I've experienced every time I've done the same thing.

Sounds very plausible. But I believe, they have been working on items that would act up? That's why I decided to mention it.

this still happens to me with food items. I'll buy 3, lock one that I want to use to feed a pet who isn't hungry now, and when I feed two other pets 2 of the item, the locked one has been fed and the one I haven't fed yet isn't locked. just so you know! it's not a huge deal like the wishlist sorting thing was, but it's not actually really always taking the unlocked item first.

Had one morty card locked, went to lock the second and it disappeared. I no longer have a second morty card in my inventory