Hello there,
I would like to report a simple, yet gamebraking bug. When you create with a wand a region with limited Y, the minY value is set as maxY and maxY value as minY in the data file.
As a result, these regions are not working at all.
I'm including two files, one with the "not swaped" values, that I've had to make manually, and the second, wrong one.

Looking forward to a fix.

Note: This bug has been there for a while (half a year I guess?)

files.zip

Have you uses claim command? If yes then 1 to 250 is protectet.
If you want your choosen area just use rp define.
As player you cant choose define because then its a server Region.
If player wants to reduce y he has to claim first and setminy and setmaxy after by command

I'm afraid both claim and define are broken.
Have you uses claim command? If yes then 1 to 250 is protectet.
That's not our case as we have set autoexpandvert-ondefine=false in the config.

On define (/pf define - to create server Region) Not on claim (rp claim - to create Player region)
Claim does not look at autoexpandvert-ondefine=false. Just define does. false is the default, just by the way. So if you use wand tool and do /rp define Name then this creates server region based on your selection. If autoexpant-on define is true then it become exrantantednfrom 1 to 256 on rp define automaticly

i took a look on your wrong and right files..

  maxY: 3
  minY: 10

why your ymin is bigger then ymax?
was this done manually by you?
i never saw this behave before :3 never happens on our server... no matter if we use claim or define

That's the issue! I thought I've explained it...
This was did by a plugin. Read my original message.
I'm also a programmer (not in Java though) and I suppose there are only min and max values swapped somewhere in the code...

We tried this too and it size where set correcly... Strengh behave...

Sending our config file. Bugging even on clean installation.
We are running latest PaperMC build, MC ver 1.16.5
config.zip

We are running a PaperMC Build server too on 1.16.5 (build 508)

here is our config may it helps <3

config.zip

here an example of a normal defined region from us (created with want tool and /rp define

Blueland:
  name: Blueland
  lastvisit: 09/03/2021
  admins: []
  members: []
  leaders:
  - '#server#@#server#'
  priority: 0
  welcome: 'Spawn '
  world: world
  maxX: 605
  maxZ: 643
  minX: -230
  minZ: -153
  maxY: 256
  minY: 0
  value: 0
  flags:
    can-grow: true
    leaves-decay: true
    allow-effects: true
    door: true
    dynmap: true
    can-projectiles: true
    portal-exit: false
    teleport: false
    allow-spawner: false
    mob-loot: false
    button: true
    pvparena: false
    allow-place: BLUE_SHULKER_BOX
    player-damage: true
    allow-magiccarpet: false
    keep-inventory: false
    fire: false
    flow: true
    iceform-player: true
    allow-home: false
    chest: true
    can-drop: true
    allow-mod: true
    iceform-world: true
    smart-door: false
    fishing: true
    use-potions: true
    cropsfarm: false
    lever: true
    pvp: false
    spawn-animals: 'true'
    passives: false
    press-plate: true
    minecart: true
    ender-chest: true
    allow-fly: true
    build: false
    allow-break: BLUE_SHULKER_BOX
    gravity: true
    flow-damage: false
    spawn-monsters: 'false'
    floristics: false
    block-transform: true
    redstone: false
    killer-projectiles: false
  candelete: true
  canpurge: true
  tppoint: ''