Island height inconsistent

[x1p]

Expected behavior

Same, consistant island height each time an island is reserved by excuting /bsb register WhateverPlayername

Observed/Actual behavior

When registering an island, the island height varies from time to time

Steps/models to reproduce

I'm registering a couple of islands. One after another.
The configured island-height is 128, the bedrock is on level 129.
Steps to reproduce:

• fly to an empty space
• execute: /bsb register MyPlayerName
• execute: /bsb unregister MyPlayerName
• check island information with /bsb info

Notice every island centre varies between x ,128, z and x ,130, z

BentoBox version

Running PURPUR 1.19.2.
BentoBox version: 1.21.0-SNAPSHOT-b2287
Database: JSON
Loaded Game Worlds:
bskyblock_world (BSkyBlock): Overworld, Nether, The End
Loaded Addons:
Biomes 2.1.0-SNAPSHOT-b235 (ENABLED)
BSkyBlock 1.15.2-SNAPSHOT-b719 (ENABLED)
Challenges 1.1.0-SNAPSHOT-b490 (ENABLED)
Level 2.9.1-SNAPSHOT-b507 (ENABLED)
Limits 1.19.1-SNAPSHOT-b300 (ENABLED)
MagicCobblestoneGenerator 2.5.0-SNAPSHOT-b251 (ENABLED)
Warps 1.13.0-SNAPSHOT-b328 (ENABLED)

Plugin list

No response

Other

I have the idea that register looks for any existing bedrock regardless of the height of that block and punt another block on top of that instead of placing a bedrock on the level it should be.