On connecting to a server the client crashes immediately. One player was building their reactor when this happened.

[21:17:15] [Render thread/FATAL]: Unreported exception thrown!
java.lang.IllegalArgumentException: null
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:131) ~[guava-31.0.1-jre.jar%2319!:?]
at it.zerono.mods.extremereactors.gamecontent.multiblock.reactor.client.ClientFuelRodsLayout.getFuelData(ClientFuelRodsLayout.java:68) ~[ExtremeReactors2-1.18.1-2.0.38.jar%2369!:1.18.1-2.0.38]
at it.zerono.mods.extremereactors.gamecontent.multiblock.reactor.part.ReactorFuelRodEntity.getUpdatedModelData(ReactorFuelRodEntity.java:133) ~[ExtremeReactors2-1.18.1-2.0.38.jar%2369!:1.18.1-2.0.38]
at it.zerono.mods.extremereactors.gamecontent.multiblock.common.part.AbstractMultiblockEntity.getModelData(AbstractMultiblockEntity.java:97) ~[ExtremeReactors2-1.18.1-2.0.38.jar%2369!:1.18.1-2.0.38]
at net.minecraftforge.client.model.ModelDataManager.refreshModelData(ModelDataManager.java:89) ~[forge-1.18.1-39.0.10-universal.jar%23102!:?]
at net.minecraftforge.client.model.ModelDataManager.getModelData(ModelDataManager.java:117) ~[forge-1.18.1-39.0.10-universal.jar%23102!:?]
at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher$RenderChunk$ChunkCompileTask.(ChunkRenderDispatcher.java:494) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher$RenderChunk$RebuildTask.(ChunkRenderDispatcher.java:524) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher$RenderChunk.m_200437_(ChunkRenderDispatcher.java:449) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.renderer.chunk.ChunkRenderDispatcher$RenderChunk.m_200434_(ChunkRenderDispatcher.java:454) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.renderer.LevelRenderer.m_194370_(LevelRenderer.java:2139) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.renderer.LevelRenderer.m_109599_(LevelRenderer.java:1172) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.renderer.GameRenderer.m_109089_(GameRenderer.java:1056) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.renderer.GameRenderer.m_109093_(GameRenderer.java:831) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.Minecraft.m_91383_(Minecraft.java:1040) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.Minecraft.m_91374_(Minecraft.java:660) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at net.minecraft.client.main.Main.main(Main.java:205) ~[client-1.18.1-20211210.034407-srg.jar%2398!:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?]
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?]
at net.minecraftforge.fml.loading.targets.CommonClientLaunchHandler.lambda$launchService$0(CommonClientLaunchHandler.java:45) ~[fmlloader-1.18.1-39.0.10.jar%2351!:?]
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-9.0.7.jar%2340!:?]
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:53) [modlauncher-9.0.7.jar%2340!:?]
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:71) [modlauncher-9.0.7.jar%2340!:?]
at cpw.mods.modlauncher.Launcher.run(Launcher.java:106) [modlauncher-9.0.7.jar%2340!:?]
at cpw.mods.modlauncher.Launcher.main(Launcher.java:77) [modlauncher-9.0.7.jar%2340!:?]
at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) [modlauncher-9.0.7.jar%2340!:?]
at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) [modlauncher-9.0.7.jar%2340!:?]
at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:90) [bootstraplauncher-0.1.17.jar:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?]
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?]
at io.github.zekerzhayard.forgewrapper.installer.Main.main(Main.java:57) [ForgeWrapper-mmc3.jar:mmc3]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?]
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?]
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:210) [NewLaunch.jar:?]
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:245) [NewLaunch.jar:?]
at org.multimc.EntryPoint.listen(EntryPoint.java:143) [NewLaunch.jar:?]
at org.multimc.EntryPoint.main(EntryPoint.java:34) [NewLaunch.jar:?]

I think I've found the problem and fixed it in dev