Skyfactory 2.5 version 2.5.6 server player kick due to fastcraft

[Tom_The_Hero]

Fastcraft is randomly kicking players on my servers and this is the error it gives:

[19:29:36] [Server thread/WARN]: Failed to handle packet for /*ip including port removed for safety*
java.lang.IndexOutOfBoundsException: Index: 57, Size: 45
at java.util.ArrayList.rangeCheck(Unknown Source) ~[?:1.8.0_121]
at java.util.ArrayList.get(Unknown Source) ~[?:1.8.0_121]
at net.minecraft.inventory.Container.func_75144_a(SourceFile:191) ~[zs.class:?]
at net.minecraft.network.NetHandlerPlayServer.func_147351_a(NetHandlerPlayServer.java:883) ~[nh.class:?]
at net.minecraft.network.play.client.C0EPacketClickWindow.func_148833_a(SourceFile:32) ~[ix.class:?]
at net.minecraft.network.play.client.C0EPacketClickWindow.func_148833_a(SourceFile:10) ~[ix.class:?]
at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:212) ~[ej.class:?]
at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:165) [nc.class:?]
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:659) [MinecraftServer.class:?]
at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:334) [lt.class:?]
at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:547) [MinecraftServer.class:?]
at fastcraft.at.a(F:978) [fastcraft-1.23.jar:?]
at fastcraft.H.aq(F:36) [fastcraft-1.23.jar:?]
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:396) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:685) [li.class:?]