[01:47:20] [WARN]: [Citizens] Task #37 for Citizens v2.0.37-SNAPSHOT (build 3727) generated an exception
java.lang.UnsupportedOperationException: null
        at it.unimi.dsi.fastutil.ints.Int2ObjectFunction.put(Int2ObjectFunction.java:73) ~[fastutil-8.5.15.jar:?]
        at Citizens (1).jar/net.citizensnpcs.nms.v1_21_R3.util.NMSImpl.replaceTrackerEntry(NMSImpl.java:1427) ~[Citizens (1).jar:?]
        at Citizens (1).jar/net.citizensnpcs.util.NMS.replaceTracker(NMS.java:814) ~[Citizens (1).jar:?]
        at Citizens (1).jar/net.citizensnpcs.npc.CitizensNPC$1.accept(CitizensNPC.java:396) ~[Citizens (1).jar:?]
        at Citizens (1).jar/net.citizensnpcs.npc.CitizensNPC$1.accept(CitizensNPC.java:357) ~[Citizens (1).jar:?]
        at Citizens (1).jar/net.citizensnpcs.npc.CitizensNPC.spawn(CitizensNPC.java:430) ~[Citizens (1).jar:?]
        at Citizens (1).jar/net.citizensnpcs.npc.CitizensNPC.load(CitizensNPC.java:188) ~[Citizens (1).jar:?]
        at Citizens (1).jar/net.citizensnpcs.api.npc.SimpleNPCDataStore.loadInto(SimpleNPCDataStore.java:79) ~[Citizens (1).jar:?]
        at Citizens (1).jar/net.citizensnpcs.Citizens$CitizensLoadTask.run(Citizens.java:543) ~[Citizens (1).jar:?]
        at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[canvas-1.21.4.jar:1.21.4-285-8c1502c]
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:474) ~[canvas-1.21.4.jar:1.21.4-285-8c1502c]
        at io.canvasmc.canvas.server.ThreadedServer.spin(ThreadedServer.java:121) ~[canvas-1.21.4.jar:1.21.4-285-8c1502c]
        at net.minecraft.server.MinecraftServer.lambda$spin$2(MinecraftServer.java:351) ~[canvas-1.21.4.jar:1.21.4-285-8c1502c]
        at java.base/java.lang.Thread.run(Thread.java:1575) ~[?:?]