Unable to shoot snowballs at a target in a minecart

Hi! I've noticed how strange minecarts act in 1.9.x . When you place down a minecart standing still, you can throw snowballs SOMETIMES as it is random. When riding a minecart you cant throw snowballs at all. This is very important to me as to a lot of other people for example using it in a gold farm to agro pigmen, so i hope you do notice this and hopefully fix it in the future updates.