Issue Description: Dynmap not rendering loaded chunks. Chunks was loaded by /wb fill. Used /dynmap fullrender and update render, still broken map.

• Dynmap Version: core=3.1-beta5-431, plugin=3.1-beta5-431
• Server Version: spigot-1.16.4
• Pastebin of Configuration.txt: https://pastebin.com/heJzdb3z
• Server Host (if applicable): https://srvgame.ru/
• Screenshots: https://ibb.co/GpQx5t9
  https://ibb.co/bLwQjH5

Duplicate of #2485

UPD: Some chunks loaded by player are not showing too.

this is what happens when dynmap is running at the same time as a wb /fill
another fullrender should once the chunks are generated should fix this. If not you need to run worldborder again with the force flag