Problem with giving item to other pet

[Bainion]

I was moving items from my pets to one another and I've discovered that if you can't give multiple items to the same pet in a row without either switching tab (going for example in map and then returning to pet) or alternating between 2 (or more) pets (for example item 1 to pet A, item 2 to pet B, item 3 to pet A, ...).
If you try to give multiple item to the same pet in a row nothing happens. Well the first transfer is done but after that nothing and without any error message or anything.
Playing on Firefox

[Anexes]

Also happens in Chrome, exact same problem.