Steps to reproduce
Spawn a sheep in a one-block space surrounded by full blocks at head-level, leaving the space accessible at foot-level.
Try to use flint & steel to light a fire under the sheep.
Behind hind the sheep at foot-level place a full-width interactable block such as a trapdoor or barrel, and to its right at foot-level place a full block.
Go into the box and push the sheep toward the left.
Stand back a few blocks and try to interact with the block behind the sheep by pointing between the sheep and the full block at foot-level.
Expected results
It is just as easy to set fire below the sheep in a 1-block space, and to interact with a block behind the sheep, as on Java Edition.
Observed results
Fire/interaction with the block below: it is harder to set fire to block below in Bedrok. On Java Edition, if you you push the sheep into the far left corner, you have about 1.5 pixels of space along the front and right of the block it stands on where you can interact. On Bedrock Edition, you have about 0.5 pixels.
Interactions with block behind: possible on Java Edition, not possible on Bedrock Edition.
In Bedrock, the area that you can break blocks under the mods is smaller than Java Edition. Mobile devices are the most who suffer with that, since is hard to place fire under mobs
Observed Results:
It's a little more difficult to set fire or break blocks below creatures. MCPE players are the ones who suffer the most from this, as they can end up accidentally hitting mobs while trying to do another activity
Expected Results:
The Bedrock area should be the same size as Java
Notes:{*}{*}
As you can see in Bedrock Edition, the area under mobs is a bit smaller, being easier to hit mobs in mobile devices
Screenshots/Videos Attached: Yes
This seems to be a property of the player hit/interaction mechanics, as opposed to mobs' collision. When hitting a mob the "width" of the hit is 0.125 blocks, so if you are pointing within 0.0625 of an entity collision box it counts as hitting the entity. The same width must be applied to checking for entity interactions as well.
I think the parity difference on this issue can be explained simply by Bedrock having the 0.125 hit/interaction width and Java not having it. The math checks out as follows:
Sheep are 0.9 blocks wide. That means they cover 14.4 pixels on each axis.
When you push a sheep to one side of a block, it leaves 1.6 pixels uncovered.
In Java Edition you can interact with the block below the sheep by pointing anywhere in the 1.6 pixel wide band. Likewise, you can shear the sheep or hit the sheep by moving the crosshair in just past 1.6 pixels from the edge of the block.
In Bedrock edition you must point at least 0.625 blocks or 1 pixel away from an entity in order to point past it. In order to interact with the block below the sheep you must point within 0.6 pixels of the edge of the block opposite the side the sheep is pushed to. Likewise, you can shear the sheep or hit the sheep by moving the crosshair in just past 0.6 pixels from the edge of the block.