Hopper Problem

Hello I was coding some command block recently but when I'm about the delayed redstone signal via hopper + comparator, I noticed some flaws.

When the hopper is facing downwards while there is a redstone signal in it, it will still transfer the items from it to the next hopper.

But when the hopper is facing sidewards with a redstone signal,
it will be suspended from transferring items to the next hopper.

I really want to know if this is intended or this is a bug. coz if it's intented I will consider it as Dev's Flaw from making the hopper suspension via redstone signal.