Error while raytracing tile (with custom perspective)

[cobalamin]

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Issue Description: dynmap spams the console with Error while raytracing tile: messages caused by java.lang.ArrayIndexOutOfBoundsException for my custom perspective.

• Dynmap Version: 3.7-beta-4-935
• Server Version: Paper 1.20.4 build git-Paper-405
• Pastebin of Configuration.txt: (absolutely unchanged over defaults)
• Server Host (if applicable): Selfhosted
• Pastebin of crashlogs or other relevant logs: Server log, worlds.txt, custom_perspectives.txt
• Other Relevant Data/Screenshots: -/-
• Steps to Replicate: I defined the worlds.txt and custom_perspectives.txt as linked above. After a /dynmap fullrender, the plugin begins to continually spam the messages as in the server log and doesn't stop (I assume until the render is finished).

[x] I have looked at all other issues and this is not a duplicate
[x] I have been able to replicate this

[JurgenKuyper]

looks to me like that block has no biome data yet