This might be a relatively silly bug to report but I've noticed that portals with the "throw_item" trigger are activated regardless of the stack's amount, consuming 1 to 64 items. It would be nice if the activation would only consume 1 item from the stack at most. (Unless you'd want to support specifying a stack size so it would have to be at least a certain amount of items.)

I can't reproduce the original issue anymore, but I'm still noticing multiple items can disappear from the stack, especially if the portal creation fails because generate_frame_if_not_found is set to false. (Though do note that I am still using version 0.36 at this moment - we'll have to update our pack again some time soon.)

As I tested it only consumes 1 item. Maybe the item stack entity teleported through the portal?