Mobs in general will not walk over short blocks (ones that are shorter than a full block, like daylight sensors). This issue has been fixed for some common blocks (like lower slabs) but not for most other blocks. This is best seen when there is only air below the short block.
Currently affected short blocks: Grind stones, beds, lecterns, stone cutters, chest, daylight sensors, end portal frame, ender chests, bells, unlit campfires, chains, conduits, and end rods.
And probably other short blocks that i forgot about
How to reproduce.
1. Go 30 blocks off the ground, and make a 1 wide by 10 long row of blocks
2. Spawn a zombie on one end, and a villager on the other end
3. Between the mobs place a couple of the above mentioned blocks in the floor
4. Neither mob will walk over the above mentioned blocks
5. Sometimes mobs can pathfind over the blocks, however, its not really.. reliable? they will often jump around, stagger, stop, or fall off the block. Best seen with the grind stone.
Expected result:
Mobs would walk over and pathfind across these blocks with little to no issue.
Full demonstration, and explanation of this bug coming soon
Not a duplicate of MCPE-47075, that report was only for slabs/soul sand/brewing stands/enchantment tables. This is a related post for all other short blocks
Related issues
is duplicated by
relates to
Attachments
Comments
migrated
migrated
Usually this only happens in a corner or between a block if the mob is on the taller block. They also do have an issue with being slowed when pathing but I covered that at (https://bugs.mojang.com/browse/MCPE-98568).
migrated
Also I can confirm.
migrated
Relates to MCPE-98568.
migrated
Mobs can kind of pathfind on chorus plants and chorus flowers,
migrated
Affects 1.16.200.55 Beta.
kmb600
affects 1.16.210.51
kmb600
affects 1.16.100
migrated
Still affects 1.16.201, or at least I'm assuming this is related. 30 second video is apparently to large to post here, so uploaded to YT.
GoldenHelmet
@Caleb Bonnell: for pathing on waterlogged blocks see MCPE-37005, and for drowned spinning around see MCPE-45645.
silentwisperer
Updated list of issue blocks
Can't pathfind at all:
unlit campfire
daylight sensor
end rod
conduit
bed
Major issues pathfinding over: (including excessive jumping, spinning, falling off)
grind stone
end portal frame
bell
lectren
chains
ender chest
chest
trapped chest
Normal pathfinding:
Soul sand, enchanting table, lower slabs.
i haven't tested lightning rods or other 1.17 blocks have not been tested, but those likely have the same issue as well.
Auldrick
Though I'm following your repro steps as given in the description, I don't see any problem with the blocks you've listed as "Can't pathfind at all" except for one thing: If end rods are mounted horizontally, there's no problem, but if mounted vertically they have the same problems as the blocks in the "Major issues" group.
Also, villagers don't have any problem with the chest, trapped chest, or ender chest; only zombies seem to.
A possible reason for the differences might be the specific release. I tested under 1.16.201 Hotfix. How about you?
migrated
Mobs don't pathfind on Moss blocks, they just say till. And if they do pathfind, they will walk in circles.
silentwisperer
Mobs can't pathfind over sculk sensors either. Same issues as listed in the above comment from myself.
GoldenHelmet
In 1.16.220 I am getting the same results as @unknown above.
migrated
Affects 1.17.40.20
migrated
Affects 1.17.30
GoldenHelmet
Use
[media]to quickly test pathing on the reported blocks. It consists of rows of 8 of each of the reported blocks, with solid blocks at either ends, and command blocks to toggle air or smooth stone under each row of blocks.
I find that the best mobs to test this with are llamas and wolves, because fleeing llamas is high-priority and long-range for wolves. Also villager + zombie testing may be impacted by the villager interaction with beds and job site blocks.
There are too many idiosyncrasies in pathing on the various blocks for me to list; it's best to just try out each one with and without solid blocks under it.
silentwisperer
It appears that this is fixed for everything \o/
Detailed testing would need to be done for every short block in the game, but from what I can tell the recent 1.18.20.21 beta fixed all the common issues 🙂
Brent101
Drowned fail to properly pathfind over enchanting tables, End portal frames, lecterns, chests, bells, cauldrons, pointed dripstone, brewing stands, composters, horizontal lightning rods, horizontal end rods, and horizontal grindstones. Turtles and axolotls get caught in a spinning loop on bells, end portal frames, brewing stands, lecterns, chests, and horizontal grindstones. Axolotls and baby turtles cannot exit composters or cauldrons. Turtles fail to pathfind over obstacles and get stuck in place as well. Otherwise, on my quick pass, most mobs pathfind correctly.
Auldrick
@unknown I was writing a comment on your original ticket MCPE-152043 when I saw you commented here. Because your affected versions include this ticket's fix version, there was a conflict, so I just tested it. This was actually fixed in 1.18.20.21 Beta and remains fixed in 1.18.20.23 Beta, for both the blocks listed above and those in your ticket. What your attached video shows isn't actually this problem, although the confusion is understandable. What your video actually shows is that drowned don't attack villagers on land during the day. If you repeat your test with the time set to night, the drowned will instantly go after the villager.
This matches the behavior drowned exhibit toward players, so it might be intentional, but I have no authoritative information either way about that. If it's not intentional, it's a bug, but it isn't what you described in your ticket so your ticket will remain closed as a duplicate of this one. If you believe it's a bug, you might want to create a new report. That report needn't mention short blocks, since they have nothing to do with the behavior.
Brent101
The time was set to night.
[media]
Auldrick
@unknown: Your videos are too short to confirm what you say, and my longer duration test with virtually the exact same setup contradicts your conclusion. The drowned do seem to delay a few seconds while they stand on a short block, but before long they climb down and start wandering around. Once they're wandering, it can take a few more seconds for them to look in the direction of a villager, at which point they target them. I don't know why they don't target them while they're still standing on short blocks; maybe it has something to do with their eye level being above the villagers' eye level. But in any case, they behave as you would expect them to within a few seconds.
Also, you didn't explain how a drowned came to be attacking a villager in this latest video. It's as if you hoped we wouldn't notice.
Brent101
These hopefully will help. And the drowned was due to testing and that I was near the seafront with mob spawning turned on. It was how I originally found out about the drowned issue being that a drowned walked on to a bell a got stuck on it.
Auldrick
Unfortunately, it looks like I haven't been testing in the version I thought I was. I was a tester for Microsoft Preview, which I still have installed. As you might know, Preview is the new way of delivering Beta releases. My Preview release was shown on the main menu as 1.18.10.23. I was confusing that with 1.18.20.23, the later version you listed as affected. I have now learned that the internal release number is 1.18.2.3, which seems to mean that my tests were done on an even older version than yours, which in turn should mean that your version should be after the fix, but the current circumstances are too special and unusual for me to be confident of any conclusion I might draw.
What I need is to test your world in the old-style Beta, the release you're using yourself, but I'm reluctant to install that given that I also have Preview installed (not to mention the problem people regularly have trying to uninstall the Beta releases). I'm going to look for another moderator who has the current Beta installed and ask for help. Check back later.
Auldrick
Moderator @unknown has tested this issue in 1.18.20.23 Beta and found that this issue is fixed for all mobs except drowned, axolotls, and turtles (apparently, aquatic mobs that can also walk on dry land). The changelog for 1.18.20.21 Beta didn't explicitly mention this bug report, but it did fix all other mobs' pathfinding, so I think the best way to handle this is to split Brent's report MCPE-152043 back out and submit it to Mojang as a separate issue.