Cleaning up old tickets: This ticket has not been updated recently (1 year+) so is being closed as Cannot Reproduce. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines.
that outline is not collision. it is actually what the game puts to represent that you are looking at the block. the actual collision is the block not highlighted. this also happens to Slabs, Stairs, Fences and, Walls. Torches, Endrods, and pressure plates do not have this
@michael s: the outline selection box is supposed to match the hitbox (where it doesn't, that's a bug: see MCPE-59928), and for blocks that have collision the collision box is the same as the hitbox. For farmland and grass paths the outline selection box is accurate to the hit/collision box. It's the hit/collision box that are wrong: they doesn't match the visual appearance or the Java Edition hit/collision boxes.
Spencer: if you look at the reports listed under "relates to" on this ticket, you will see that there is already a separate report for soul sand. The issue with soul sand is not included on this ticket because it started in a different version.
Fixing this bug would automatically fix other issues that result from it without any other code changes, including MCPE-33288, MCPE-33575, MCPE-34268, and MCPE-61257.
However, a simple fix might cause grass path and farmland to be affected by MCPE-124841 instead. That would probably be worse.
Smaller blocks like farmland, dirt path, and slabs generally don't update themselves.
Example: Place a block of farmland on the ground, place a slab on top of it and then take it out. You will notice that the farmland block will not become a dirt block.
Please note: it may look like I'm standing on the grass block in the screenshot but I am not