is create has a NullPointerException on cache

[Euphillya]

Error :

[12:59:35 WARN]: [Skyllia] Async task for Skyllia v1.0-158 generated an exception
java.lang.NullPointerException: null
        at java.base/java.util.concurrent.ConcurrentHashMap.putVal(ConcurrentHashMap.java:1011) ~[?:?]
        at java.base/java.util.concurrent.ConcurrentHashMap.put(ConcurrentHashMap.java:1006) ~[?:?]
        at Skyllia-1.0-158-all.jar/fr.euphyllia.skyllia.cache.PlayersInIslandCache.add(PlayersInIslandCache.java:50) ~[Skyllia-1.0-158-all.jar:?]
        at Skyllia-1.0-158-all.jar/fr.euphyllia.skyllia.cache.CacheManager.updateExecCacheIsland(CacheManager.java:95) ~[Skyllia-1.0-158-all.jar:?]
        at Skyllia-1.0-158-all.jar/fr.euphyllia.skyllia.cache.CacheManager.lambda$updateCacheIsland$3(CacheManager.java:87) ~[Skyllia-1.0-158-all.jar:?]
        at io.papermc.paper.threadedregions.scheduler.FoliaAsyncScheduler$AsyncScheduledTask.run(FoliaAsyncScheduler.java:219) ~[bloomexcalia-1.21.3.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:1583) ~[?:?]