Wyatt Boyle

Confirmed in 1.19.4 still

Hello, I would argue that this isn't necessarily a duplicate, as you can actually sleep in the bed which prevents phantoms from spawning, and you can indeed have two dimensions with the "type":"minecraft:overworld" type, or simply use the bed_works boolean. The bug part is that it doesn't actually advance the night on successful sleep, which wasn't mentioned in the original post whatsoever, but I guess I could be persuaded to say this is somehow a feature request, for sleeping to fully work in custom dimensions, but that's all I wanted to add. 

However in imported dimensions (using datapacks) for minecraft 1.16 pre-release 3, the seed for biomes and terrain is fixed to what the file sets as the seed, and you can't leave the seed field out of the .json without it throwing an error.  I feel that the world file seed should specify what generates in the imported dimension, otherwise all imported dimensions will be exactly the same and have no variety, ruining the exploration factor of imported extra dimensions.

Well I just tested it in 1.8.9 and boats can be teleported upwards while players are still riding in them, I do not know why they listed 1.8 as an affected version, but to the "only boats are affected" I'm not sure, I didn't submit the glitch I only am saying what I know, if you think that if the other glitch is solved it will solve this then sure, mark this as a duplicate, it's not my area of knowledge.

This bug was actually caused by minecraft 1.9 boats, this was not an issue with boats before then, I don't remember why this wasn't a duplicate for the one you listed, but it's usually been treated separate.

still an issue in the latest snapshot, 16w42a.

The comment just above me, describing that boats can only be teleported on the x and z axis are still true in the latest snapshot 16w42a. Although I found it would not tolerate any amount of up or down teleportation at all.

In the latest snapshot 16w42a, when spawning the lava slime and hitting it, it shoots a large amount of hearts out, that I can only guess would equal it's full health, like it produces mass amounts of the heart particle and does not die on the first hit, but then dies when I hit it two more times with my fist. I am not sure if this confirms or changes the glitch, but that is what I found.

In the latest snapshot, 16w42a, the damage is still the same when following the instructions posted. Yet when using the command

summon MOB_TYPE_HERE ~ ~1 ~ {Attributes:[{Name:"generic.attackDamage",Base:10D}]}

they do not attack any harder than normal, YET when I attack them, they produce what looks to be 5 full hearts or so of damage, and no matter the size, they will not die on the first hit (I hit a tiny slime and it produced the large amount of hearts, and did not die when I hit it), upon hitting them again they will go back to normal behavior, of course still not dealing any extra damage to me (yes I tested it on a slime that could deal damage to me as well)

The message still happens in the latest snapshot 16w42a

It does appear to be fixed in the latest snapshot 16w42a

A workaround for the current update of 1.9: use "/execute @a ~ ~ ~ " and add an appropriate range to the second "/execute", I am not entirely sure if adding something over a certain amount causes the bug to re-occur, but this should work, just use a large radius and it should work just as well. Just make sure to do testing while making any command block things to make sure it if it works.

The original title was inaccurate as to the cause of the bug, before it said that simply unloading a chunk would cause the entity to have it's scoreboard value reset, when in reality that is not exactly true, it is that when an entity has a /execute command with a detect part attached to it, for example "/execute @e[type=Pig] ~ ~ ~ detect ~ ~ ~ minecraft:air 0", when it's chunk becomes unloaded, it causes all scoreboard values for the entity and all other entities within the chunk to be reset.

Okay, after like 5 hours of testing I have a new suggested title "/execute detect command causing entities within a chunk to be scoreboard reset" and i will explain why.
What I have found is the steps to re-produce in any world, no matter the tick rate, (I have only tested in singleplayer but I assume multiplayer does this too since you all have said you have opened to lan and reproduced it)
1) Spawn in a world, just do superflat to make it easier (also make the world creative mode )
2) use /setworldspawn, and mark the spawn with anything you choose, just so you know where your spawn was
3) give yourself a command block, and place it down anywhere as long as it should be in a spawn chunk, so near where you marked.
4) enter this into the command block:

/execute @e[type=Armor_Stand,name=Test] ~ ~ ~ detect ~ ~ ~ minecraft:air 0 /say @p[r=1] testing

(sometimes the command block may not register it should be always active, so you may need to toggle that again)
5) make it a repeat command block along with always active
6) teleport 500 blocks away in any direction (although 300 seems to fine as well {MY RENDER DISTANCE: 10 chunks}, as long as the chunk un-loads from view)
7) mark out the chunk you are in, and use this command inside of that chunk:

/summon minecraft:armor_stand ~ ~ ~ {CustomName:Test}

(you should see the command block begin to make it say "(your_name) testing", just step away from it a bit)

8) now place another armorstand OUTSIDE that chunk, just place it down using any method using the default item even
9) Now use these commands with both armorstands in view

/scoreboard objectives add Test dummy
 /scoreboard players set @e[type=Armor_Stand,c=1,name=Test] Test 1
/scoreboard players set @e[type=Armor_Stand,c=1,name=!Test] Test 2
/scoreboard objectives setdisplay sidebar Test

(that should make both appear on the scoreboard)

10) Now go back to spawn using any method you choose, teleport or flying/walking back
11) The one with the score of 1 should disapear off the scoreboard, and the other one should stay on the scoreboard, if not, then place a block or something else to update chunks in the world.
There, that should succesfully re-produce the bug.
Some interesting facts:
-If you put MORE armorstands (with scoreboard values set) into the chunk that the "Test" armorstand is in, they ALSO will have their scores reset, yet the armorstand outside of the chunk will keep it's scoreboard value.
-If you make the command in the command block into:

/execute @e[type=Armor_Stand,name=Test] ~ ~ ~ /say @p[r=1] testing

and then go back over (making sure both armorstands have their scores set to 1 and 2) and then come back, it will not reset their scores.
--If you remove the name parameter from the command block to make it:

/execute @e[type=Armor_Stand] ~ ~ ~ detect ~ ~ ~ minecraft:air 0 /say @p[r=1] testing

and then go back over (making sure both armorstands have their scores set to 1 and 2) and then come back, BOTH should have their scores reset when the chunk becomes unloaded

-If a score is not unloaded when I said it would be, again try placing blocks, moving around, or re-loading the world possibly, to cause the chunk to properly unload from the world, sometimes teleporting can leave a chunk loaded for a moment or two. (Sometimes clicking the command block then clicking out of it can cause chunk updates as well.) Or check if the command block is always active, as in making it "needs redstone", clicking done, then clicking back in and making it "always active".

EDIT: made it so the commands still work in the latest snapshot, but god knows why mojang decided to make it armor_stand, but the commands should work now

confirmed in 1.9.2 and 1.9.4

Still an issue in 1.9.4

still in 1.9.4

still an issue in 1.9.4, I add a score to an entity, (I've tried different score types like dummy and item.stick.use), display it to the sidebar, then leave the area and when the chunk becomes unloaded the score resets on any entity inside. This glitch happens in my worlds even when the amount of command blocks is low, and in singleplayer.

Still an issue in 1.9.4

still an issue in 1.9.4