I don't know what it is

[AllFiRE0]

[21:36:37] [Craft Scheduler Thread - 269 - CMI/WARN]: [CMI] Plugin CMI v9.8.4.5 generated an exception while executing task 296897
java.lang.UnsupportedOperationException
at java.base/java.util.ImmutableCollections.uoe(ImmutableCollections.java:142) ~[?:?]
at java.base/java.util.ImmutableCollections$AbstractImmutableCollection.add(ImmutableCollections.java:147) ~[?:?]
at CMI-9.8.4.5.jar//com.Zrips.CMI.Modules.Holograms.CMIHologram.(CMIHologram.java:215) ~[?:?]
at CMI-9.8.4.5.jar//com.Zrips.CMI.Modules.PlayerCombat.PlayerCombatManager.lambda$11(PlayerCombatManager.java:895) ~[?:?]
at CMILib1.5.8.2.jar//net.Zrips.CMILib.Version.Schedulers.CMIBukkitImpl.lambda$runTaskAsynchronously$1(CMIBukkitImpl.java:48) ~[?:?]
at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[leaf-1.21.11.jar:1.21.11-DEV-9ddd817]
at org.bukkit.craftbukkit.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:57) ~[leaf-1.21.11.jar:1.21.11-DEV-9ddd817]
at com.destroystokyo.paper.ServerSchedulerReportingWrapper.run(ServerSchedulerReportingWrapper.java:22) ~[leaf-1.21.11.jar:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]
at java.base/java.lang.Thread.run(Thread.java:1570) ~[?:?]