[Solved] java.lang.IllegalArgumentException: Team §a already exists in this scoreboard - Kicked out while joining the game

(Using translation software, the content may look strange, sorry)
I am using BedWars1058-23.3, the servers are paper-1.18.2-388 and waterfall-1.18-488,

serverType: BUNGEE_LEGACY

The moment a player joins the Arena from the lobby, it is kicked out of the Arena and returned to the lobby. Arena console has no exception (ikun lost connection: Disconnected), the following error appeared on the Waterfall console:
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[14:16:41 ERROR]: [/127.0.0.1:57005|ikun] <-> DownstreamBridge <-> [bedwars4_testmap1] - encountered exception
java.lang.IllegalArgumentException: Team §a already exists in this scoreboard
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:220) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at net.md_5.bungee.api.score.Scoreboard.addTeam(Scoreboard.java:73) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at net.md_5.bungee.connection.DownstreamBridge.handle(DownstreamBridge.java:248) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at net.md_5.bungee.protocol.packet.Team.handle(Team.java:124) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at net.md_5.bungee.netty.HandlerBoss.channelRead(HandlerBoss.java:114) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:986) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[waterfall-1.18-488.jar:git:Waterfall-Bootstrap:1.18-R0.1-SNAPSHOT:5661172:488]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
[14:16:41 INFO]: [ikun] disconnected with: The server you were previously on went down, you have been connected to a fallback server