Even every snapchot?
But this isn't how it's supposed to work. Was there some change to hoppers that I'm not aware of? Because as long as I know, items should go to the lowest hopper, then to the lowest chest. If that hopper chest fill up, items go to the second from the bottom chest and so on. They shouldn't split. Am I wrong?
Well, I've tested every full release from 1.6 to 1.11.2 and it seems like the hoppers are behaving the same way, and I think that they will behave in the newer versions too. However, I think I came up with a solution. Since when a chest is an input, it slows down the hoppers item pulling, therefore item pulling, so I just need to place a single chest inbetween the hoppers.
Conclusion: If I want the sorter working properly, I have to use a chest, or a hopper going sideways.
Also, this is just my opinion, but i think this isn't how hoppers should work. I think they should be pulling items slower, not 2 at a time and they should be checking if there is a hopper underneath them everytime, even if there's 2 items in there.