Treasure map generation don't respect default setting

[patokeni]

Expected behavior

Treasure maps should always be filled with the location of a nearby treasure regardless of whether it has been located by another map or not, which I believe is the vanilla behavior and default setting.

Observed/Actual behavior

After first treasure map was generated, subsequent treasure maps become effectively empty maps and only a name left.

Steps/models to reproduce

1. Create a new world.
2. Find several shipwreck and get the treasure maps.
   If we just create a new world, everything seems to work just fine, except every time a map gets generated, a new treasure is located. But if we explored all the treasure around a specific area, when a new map around here is needed to be generated, the server would struggle to find a new treasure, which I think caused a empty map to be generated (and cause lag).

Plugin and Datapack List

Not related.

Paper version

This server is running Paper version git-Paper-100 (MC: 1.20.1) (Implementing API version 1.20.1-R0.1-SNAPSHOT) (Git: f402f89)

Other

Inside ExplorationMapFunction.java we could see !serverLevel.paperConfig().environment.treasureMaps.findAlreadyDiscoveredLootTable.or(!this.skipKnownStructures) is replacing the vanilla this.skipKnownStructures. From vanilla loot tables we could know this.skipKnownStructures should be false. But the changed code is resulting a true by default whatever the loot table specify. Look into it deeper, it seems that the BooleanOrDefault class did not respect the default value. I don't know whether this is intended or not.

[Machine-Maker]

Yep, your analysis is spot on. Looks like somehow the fallback value in BooleanOrDefault was just completely ignored. Will be fixed with #9572