redstone item splitter drops all items into 1 hopper

I am trying to replicate this design.

So far, I am making a copy of it, block to block, in my survival and creative worlds. They both lead to 1 result - all items are getting sent to 1 channel.

In his video I can see how first set of comparators flashes one by one, but in my case they seem to be off all the time;

1. Does it still work or is it some outdated model?
2. What is a potential issue with the way I do it?

Solution 1:

If the comparators are off that means there is no item in the droppers. You need to put a single item in one of the droppers to activate this circuit.

Solution 2:

Look at the left side of your screenshot; you are using glass. Notice how the redstone signal can’t travel down steps made of glass.

You can remedy this issue by replacing them with solid blocks.