This is really annoying. It's nearly 2020, no reason to click things one by one.

Yeah, I've had this happen when reading the same book to manymany pets. It's super annoying.

I disable stacking in my inventory options and I often end up with a bunch of items with no ID number at all. Just https://subeta.net/item.php?n_id= in the URL bar. The first item in the bunch works fine and has an ID. Everything after the first item? Blank IDs. Re-stacking and unstacking does nothing. Vaulting and adding them back to my inventory does nothing. I didn't try quickstocking them into a shop to try and force them to acquire ID numbers.

Only noticed this happening with stacked items, too.

Tested and can concur, when you have multiples of 1 item, only the first item in an unstacked inventory is assigned item ID, and rest are blank

IE if I have 5 Lightweight Egg in my unstacked inventory, and if I wanted to use them all on 1 pet and want to load pages of 1 item per page, only the first Lightweight Egg is able to be used, the balance 4 will have opened with "https://subeta.net/item.php?itemid=" & the following error

yes it is.

Although sometimes, when I'm reading stacks of books to different pets, it will let me read a couple before giving the invalid error.