Set with Polygon Selection throws NullPointerException

[Damowerko]

Bug report for FastAsyncWorldEdit 1.14.4

[REQUIRED] FastAsyncWorldEdit Configuration Files:

latest.log
config.txt
config-legacy.txt

[REQUIRED] FastAsyncWorldEdit Version Number:

[01:40:39 INFO]: FastAsyncWorldEditunknown created by Empire92
[01:40:39 INFO]: Wiki: https://github.com/IntellectualSites/FastAsyncWorldEdit-1.13/wiki
[01:40:39 INFO]: ------------------ Platforms ------------------

• Bukkit-Official(1.15-130;85b6566)

[01:40:39 INFO]: ---------------- Capabilities ----------------
GAME_HOOKS: Bukkit-Official
CONFIGURATION: Bukkit-Official
USER_COMMANDS: Bukkit-Official
PERMISSIONS: Bukkit-Official
WORLDEDIT_CUI: Bukkit-Official
WORLD_EDITING: Bukkit-Official

[REQUIRED] Spigot/Paper Version Number:

[01:40:58 INFO]: This server is running Paper version git-Paper-142 (MC: 1.15.2) (Implementing API version 1.15.2-R0.1-SNAPSHOT)
[01:40:58 INFO]: Checking version, please wait...
[01:40:59 INFO]: You are running the latest version

[REQUIRED] Description of the problem:

When I try to use the //set command with a polygon selection I get a null pointer error. I expect that if I select a small poly made out of 4 adjacent blocks use //set 0 that they should be replaced by air. Instead a NullPointerException is thrown.

How to replicate:

1. Use polygon select //sel poly air
2. Select a square on the ground, 4 adjacent blocks.
3. //set 0.

Plugins being used on the server:

BKCommonLib, dynmap*, Essentials, EssentialsSpawn, FastAsyncWorldEdit, LightCleaner, LuckPerms, PluginConstructorAPI, ServerRestorer, Vault, WorldEdit, WorldGuard

Checklist:

• I included all information required in the sections above
• I made sure there are no duplicates of this report (Use Search)
• I made sure I am using an up-to-date version of FastAsyncWorldEdit for 1.14.4
• I made sure the bug/error is not caused by any other plugin