I'm developing a Minecraft server that requires MultiverseCore and whenever I log into the server and try to teleport into another world, I get the following message:

[00:17:35 WARN]: java.lang.IllegalArgumentException: Modifier is already applied on this attribute!
[00:17:35 WARN]:        at net.minecraft.world.entity.ai.attributes.AttributeInstance.addModifier(AttributeInstance.java:80)
[00:17:35 WARN]:        at net.minecraft.world.entity.ai.attributes.AttributeInstance.addPermanentModifier(AttributeInstance.java:106)
[00:17:35 WARN]:        at net.minecraft.world.entity.ai.attributes.AttributeInstance.addPermanentModifiers(AttributeInstance.java:112)
[00:17:35 WARN]:        at net.minecraft.world.entity.ai.attributes.AttributeMap.lambda$assignPermanentModifiers$7(AttributeMap.java:120)
[00:17:35 WARN]:        at it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap$1.forEach(Object2ObjectOpenHashMap.java:1188)
[00:17:35 WARN]:        at net.minecraft.world.entity.ai.attributes.AttributeMap.assignPermanentModifiers(AttributeMap.java:117)
[00:17:35 WARN]:        at net.minecraft.server.level.ServerPlayer.restoreFrom(ServerPlayer.java:2289)
[00:17:35 WARN]:        at net.minecraft.server.players.PlayerList.respawn(PlayerList.java:787)
[00:17:35 WARN]:        at org.bukkit.craftbukkit.entity.CraftPlayer.teleport(CraftPlayer.java:1520)
[00:17:35 WARN]:        at org.bukkit.craftbukkit.entity.CraftPlayer.teleport(CraftPlayer.java:1377)
[00:17:35 WARN]:        at org.bukkit.craftbukkit.entity.CraftEntity.teleport(CraftEntity.java:229)
[00:17:35 WARN]:        at multiverse-core-4.3.14.jar//com.onarandombox.MultiverseCore.utils.SimpleSafeTTeleporter.safelyTeleport(SimpleSafeTTeleporter.java:215)
[00:17:35 WARN]:        at multiverse-core-4.3.14.jar//com.onarandombox.MultiverseCore.utils.SimpleSafeTTeleporter.teleport(SimpleSafeTTeleporter.java:338)
[00:17:35 WARN]:        at multiverse-core-4.3.14.jar//com.onarandombox.MultiverseCore.commands.TeleportCommand.runCommand(TeleportCommand.java:152)
[00:17:35 WARN]:        at multiverse-core-4.3.14.jar//com.onarandombox.commandhandler.CommandHandler.checkAndRunCommand(CommandHandler.java:296)
[00:17:35 WARN]:        at multiverse-core-4.3.14.jar//com.onarandombox.commandhandler.CommandHandler.processFoundCommands(CommandHandler.java:143)
[00:17:35 WARN]:        at multiverse-core-4.3.14.jar//com.onarandombox.commandhandler.CommandHandler.locateAndRunCommand(CommandHandler.java:93)
[00:17:35 WARN]:        at multiverse-core-4.3.14.jar//com.onarandombox.MultiverseCore.MultiverseCore.onCommand(MultiverseCore.java:839)
[00:17:35 WARN]:        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45)
[00:17:35 WARN]:        at io.papermc.paper.command.brigadier.bukkit.BukkitCommandNode$BukkitBrigCommand.run(BukkitCommandNode.java:82)
[00:17:35 WARN]:        at com.mojang.brigadier.context.ContextChain.runExecutable(ContextChain.java:73)
[00:17:35 WARN]:        at net.minecraft.commands.execution.tasks.ExecuteCommand.execute(ExecuteCommand.java:31)
[00:17:35 WARN]:        at net.minecraft.commands.execution.tasks.ExecuteCommand.execute(ExecuteCommand.java:19)
[00:17:35 WARN]:        at net.minecraft.commands.execution.UnboundEntryAction.lambda$bind$0(UnboundEntryAction.java:8)
[00:17:35 WARN]:        at net.minecraft.commands.execution.CommandQueueEntry.execute(CommandQueueEntry.java:5)
[00:17:35 WARN]:        at net.minecraft.commands.execution.ExecutionContext.runCommandQueue(ExecutionContext.java:103)
[00:17:35 WARN]:        at net.minecraft.commands.Commands.executeCommandInContext(Commands.java:448)
[00:17:35 WARN]:        at net.minecraft.commands.Commands.performCommand(Commands.java:355)
[00:17:35 WARN]:        at net.minecraft.commands.Commands.performCommand(Commands.java:342)
[00:17:35 WARN]:        at net.minecraft.commands.Commands.performCommand(Commands.java:337)
[00:17:35 WARN]:        at net.minecraft.server.network.ServerGamePacketListenerImpl.performUnsignedChatCommand(ServerGamePacketListenerImpl.java:2241)
[00:17:35 WARN]:        at net.minecraft.server.network.ServerGamePacketListenerImpl.lambda$handleChatCommand$11(ServerGamePacketListenerImpl.java:2215)
[00:17:35 WARN]:        at net.minecraft.server.TickTask.run(TickTask.java:18)
[00:17:35 WARN]:        at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:154)
[00:17:35 WARN]:        at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:24)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:1576)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:207)
[00:17:35 WARN]:        at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:128)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.pollTaskInternal(MinecraftServer.java:1553)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:1546)
[00:17:35 WARN]:        at net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:138)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.managedBlock(MinecraftServer.java:1497)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.waitUntilNextTick(MinecraftServer.java:1507)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1343)
[00:17:35 WARN]:        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:339)
[00:17:35 WARN]:        at java.base/java.lang.Thread.run(Thread.java:1583)