Java Edition:Half Double Chest
During 1.13-pre6, a bug occurred when double chests were generated over a chunk boundary.[1] Half of the double chest would remain a double chest, and the other half convert to a single chest.
Obtaining
Generation
This bug only generates in woodland mansions, and possibly in specific dungeons, since they were the only structures that generated double chests. Furthermore, it only generates in one room of a woodland mansion, the "large storage room". Within this room, there are seven separate chances for a chunk boundary to intercept a double chest, however, due to another bug,[2] only half of these rooms actually generated double chests in the first place. This bug is incredibly rare, and only four examples are currently known: Seed -9081407751656513996 at 5344, 65, -10922, Seed 1224178737854011034 at 18443, 68, -68436, Seed 105560318 at -9839 73 -7108, and Seed -8319794722483450039 at -3453 66 4051 (tested in 1.16.5). Theoretically, the bug could also occur in another room in woodland mansions called the "small storage room" -however, it would be substantially more rare, due to only two chances for a chunk boundary to intercept a double chest. An even rarer variant could be possible if a chunk boundary intercepted a double chest dungeon. Currently there has not been an example found in the "small storage room", or in a double chest dungeon.
Updating
When these chests are generated in 1.13-pre6 a type "right" half double chest appears normal, whereas a type "left" appears invisible. Updating to 19w39a through 19w41a (1.15 snapshots) causes the type "left" chest to no longer appear invisible, and have the same texture as the type "right" chest. Updating to 19w42a (1.15 snapshot) until 1.21 (present) also changes the appearances so they no longer collide with the adjacent chest. Blocks can be placed and broken adjacent to a half double chest, the only exception being chests, which update the half double chest and convert it to a single chest. The half double chest can also be opened, and items can be stored inside.
Gallery
A type "right" half double chest during 1.13-pre6 - 19w41a
A type "left" half double chest during 1.13-pre6 - 19w38b
A type "right" half double chest from 19w42a - 1.21 (present)
A type "left" half double chest from 19w42a - 1.21 (present)
A type "right" half double chest from unknown - 1.16.5 (doesn't generate on the same seed in 1.17)
