This bug affects only dropped items and not people, mobs or Armour stands. It was discovered by Mumbo Jumbo in a Honey Block testing video: https://youtu.be/SLqwJ2tmYNE?t=131
Please see the attachments below for a visual.
If you are facing a honey block and thrown a item at it directly, it will slow down from the normal drop speed and fall down the block to the bottom.
However, if you align yourself to the side of the honey block and look across the face, you will see that throwing a block means it continues on a normal horizontal trajectory despite it being slowed down.
It should glide across the face of the block, slow down, and then fall vertically down the face. This does not happen.
Related issues
is duplicated by
relates to
Attachments
Comments

I don't think this is a bug, seems intentional to me. But I can be wrong.

It makes no sense. The item should slow down and just fall straight vertically down. In this case, the item only slows down by half in the horizontal motion but does not arc downwards at all.

Please do not mark unreleased versions as affected.
You don't have access to them yet.