This bug is currently happening to me in the server console:
! [Wed 16:30:45 WARN Skywars] Task #680928 for Skywars v5.6.29 generated an exception
java.lang.NullPointerException: Cannot invoke "org.bukkit.World.getPlayers()" because the return value of "com.walrusone.skywarsreloaded.game.GameMap.getCurrentWorld()" is null
at SkyWarsReloaded 5.6.29.jar//com.walrusone.skywarsreloaded.managers.MatchManager$6.run(MatchManager.java:761)
at org.bukkit.craftbukkit.v1_20_R3.scheduler.CraftTask.run(CraftTask.java:101)
at org.bukkit.craftbukkit.v1_20_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:482)
at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1636)
at net.minecraft.server.dedicated.DedicatedServer.tickChildren(DedicatedServer.java:447)
at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1515)
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1216)
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319)
at java.base/java.lang.Thread.run(Thread.java:840)
Another bug is that after players finish a game, they get stuck in the world/void, and they can't go back or do anything. Players can also kill them for some reason. I believe the plugin/server still think that they are in the game.