Throwing this warn when you shut down the server
[10:45:01 WARN]: java.lang.NullPointerException: Nodes must be provided. [10:45:01 WARN]: at org.yaml.snakeyaml.nodes.NodeTuple.(NodeTuple.java:26) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.representMapping(BaseRepresenter.java:181) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.SafeRepresenter$RepresentMap.representData(SafeRepresenter.java:330) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.file.YamlRepresenter$RepresentConfigurationSection.representData(YamlRepresenter.java:31) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.representData(BaseRepresenter.java:111) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.representMapping(BaseRepresenter.java:174) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.SafeRepresenter$RepresentMap.representData(SafeRepresenter.java:330) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.representData(BaseRepresenter.java:111) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.represent(BaseRepresenter.java:81) [10:45:01 WARN]: at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:285) [10:45:01 WARN]: at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:253) [10:45:01 WARN]: at org.yaml.snakeyaml.Yaml.dump(Yaml.java:231) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.file.YamlConfiguration.saveToString(YamlConfiguration.java:37) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.file.FileConfiguration.save(FileConfiguration.java:55) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.properties.PropertyType.set(PropertyType.java:148) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.properties.PropertyType.fset(PropertyType.java:165) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.properties.PropertyType.fset(PropertyType.java:155) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.spawning.spawners.MythicSpawner.saveSpawnerData(MythicSpawner.java:301) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.spawning.spawners.SpawnerManager.lambda$saveSpawners$0(SpawnerManager.java:130) [10:45:01 WARN]: at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.spawning.spawners.SpawnerManager.saveSpawners(SpawnerManager.java:130) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.config.ConfigExecutor.lambda$save$0(ConfigExecutor.java:170) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.Delegates$RunnableToSupplier.get(Delegates.java:121) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.promise.LuminePromise$SupplyRunnable.run(LuminePromise.java:654) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.tasks.LumineExecutors$SchedulerWrappedRunnable.run(LumineExecutors.java:70) [10:45:01 WARN]: at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) [10:45:01 WARN]: at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [10:45:01 WARN]: at java.base/java.lang.Thread.run(Thread.java:833) [10:45:01 WARN]: java.lang.NullPointerException: Nodes must be provided. [10:45:01 WARN]: at org.yaml.snakeyaml.nodes.NodeTuple.(NodeTuple.java:26) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.representMapping(BaseRepresenter.java:181) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.SafeRepresenter$RepresentMap.representData(SafeRepresenter.java:330) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.representData(BaseRepresenter.java:111) [10:45:01 WARN]: at org.yaml.snakeyaml.representer.BaseRepresenter.represent(BaseRepresenter.java:81) [10:45:01 WARN]: at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:285) [10:45:01 WARN]: at org.yaml.snakeyaml.Yaml.dumpAll(Yaml.java:253) [10:45:01 WARN]: at org.yaml.snakeyaml.Yaml.dump(Yaml.java:231) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.file.YamlConfiguration.saveToString(YamlConfiguration.java:37) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.file.FileConfiguration.save(FileConfiguration.java:55) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.properties.PropertyType.set(PropertyType.java:148) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.properties.PropertyType.fset(PropertyType.java:165) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.config.properties.PropertyType.fset(PropertyType.java:155) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.spawning.spawners.MythicSpawner.saveSpawnerData(MythicSpawner.java:301) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.spawning.spawners.SpawnerManager.lambda$saveSpawners$0(SpawnerManager.java:130) [10:45:01 WARN]: at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.spawning.spawners.SpawnerManager.saveSpawners(SpawnerManager.java:130) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.core.config.ConfigExecutor.lambda$save$0(ConfigExecutor.java:170) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.Delegates$RunnableToSupplier.get(Delegates.java:121) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.promise.LuminePromise$SupplyRunnable.run(LuminePromise.java:654) [10:45:01 WARN]: at MythicMobs-5.4.0-SNAPSHOT.jar//io.lumine.mythic.bukkit.utils.tasks.LumineExecutors$SchedulerWrappedRunnable.run(LumineExecutors.java:70) [10:45:01 WARN]: at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) [10:45:01 WARN]: at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [10:45:01 WARN]: at java.base/java.lang.Thread.run(Thread.java:833)