Pistons push items the wrong way

Confirmed in 1.5pre.

Confirmed. Happens even when there are solid blocks in the middle.

I have discovered that this behavior of items passing through non-full blocks can actually be helpful, like in Practical Uses for example.
Although in that example i'm not sure that the eggs actually pass through the half-slab, or are sucked right away.
I would like someone to clarify what happens in this situation, please.

The half-slab on top of the hopper serves the purpose of avoiding chikens falling through the hopper, like in MC-25365

What would really need an improvement is the physics behind the Drops.
Sometimes, when a chicken is burned or a piston pushes a melon or a sugarcane, for example, the Drops get all over the place, it's like they explode!
Also, when pushed by a piston, Drops can sometimes travel backwards or get stuck in the gap of the piston arm, like in Gap Fall

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

Updated. I thought that once a bug would be 'confirmed' it would remain on a check list until it would be 'fixed'.
In my previous comment, I may have a couple of individual bugs, but I'm unsure whether or not I should create individual issues for them.

I'm unable to recreate this in 1.18.2 & 22w18a

This is NOT a bug. It is a consequence of 2 perfectly intentional features:

• glass pane connecting to adjacent blocks upon shape updated

• Entities attempting to escape when their hitbox overlaps with any blocks: Entity.class method `pushOutOfBlocks`, which is used by item entities in their `tick()` method. Fixing this would be nonesense. 

It is also NOT related to https://bugs.mojang.com/browse/MC-278182 , as this is not an intended feature, but rather a mistake from mojang developers

All other entities are pushed correctly, it's just items that are misbehaving here. Yes them being pushed out of collisionboxes is intended, but they shouldn't end up inside the collision box to begin with, after all, the sugar cane breaks the moment the other block starts moving, so the item shouldn't be appearing inside that block.

There's your mistake. The issue isn’t with the entity itself. Instead, the item is summoned and pushed by the piston. A few game ticks later, the piston block entity completes its extension. At that point, a block suddenly appears where the item entity was originally located (glass pane instantly connecting upon shape update).
As I said earlier, it is the consequence of multiple, perfectly intentional behaviors.

Items do not end up inside the collision box, but rather the block ends up where the item is (it also does not happen in gt0, but a couple gt's after). Not a bug

Pistons push entities forward, as do blocks moves by pistons; that the item isn't pushed by the moving block is the problem here. Take a look at gap_fall. png, that has no glass pane that connects to blocks, yet still launched the item out.