Item elevators not working properly

When using a generic glass item elevator using a dropper and a hopper picking up the items, the hopper fails to pick up the dispensed items and they get stuck in the hopper line. When using a water stream to pick up the items, there is no issue.

I have tested this issue by using four item elevators: a glass one in world 1 using hoppers, a stone brick one in world 1 using hoppers, a glass one in world 1 using water streams and a glass one in world 2 using hoppers.
The result is that none of these item elevators work, with the exception of the water stream elevator. This means it is not a world-related bug and is a consistent glitch.