This is how it has been for some time now. I think the change occured quite some time ago. And it can also fire more than 2 shots.
This is also how other ranged units (ships, railguns) work now.
Edit to add: I feel that it can sometimes be a bad tactic to send single infantry to feed enemy artillery stacks. This is because the enemy stack will gain ~1-2% morale for each single-infantry stack they kill. How detrimental it is depends a lot on the composition of the enemy stack. If they have 1000 infantry in the artillery stack, then it is very detrimental. If the stack is mostly artillery and has little infantry, then the effect of this is negligible.