So you should probably open a bug report at the relevant forum, containing the info you provided and the screenshots of the code parts I did post (those are only two cases, the issue can be found at much more, as you did already notice).
Thank you for the quick answer. Strangely enough, the recipes work as intended. So the snowy Angmar bricks from your first example use up only one brick and one snowball, but according to the code, they should use four.
Or do I misunderstand something? Or do recipes in general only use one item per input slot and do not care for the numbers at all?