java.lang.NullPointerException: Cannot invoke "String.isEmpty()" because "$$0" is null
at net.minecraft.class_2519.method_23256(class_2519.java:71) ~[server-intermediary.jar:?]
at net.minecraft.class_2487.method_10582(class_2487.java:231) ~[server-intermediary.jar:?]
at com.github.clevernucleus.opc.impl.PlayerCacheImpl.toNbt(PlayerCacheImpl.java:150) ~[opc-0.0.1-1ec1f86740e295df.jar:?]
at net.minecraft.class_31.handler$cjp000$onUpdateProperties(class_31.java:697) ~[server-intermediary.jar:?]
at net.minecraft.class_31.method_158(class_31.java) ~[server-intermediary.jar:?]
at net.minecraft.class_31.method_163(class_31.java:231) ~[server-intermediary.jar:?]
at net.minecraft.class_32$class_5143.method_27426(class_32.java:340) ~[server-intermediary.jar:?]
at net.minecraft.server.MinecraftServer.method_3723(MinecraftServer.java:568) ~[server-intermediary.jar:?]
at net.minecraft.server.MinecraftServer.method_3782(MinecraftServer.java:613) ~[server-intermediary.jar:?]
at net.minecraft.class_3176.method_3782(class_3176.java:567) ~[server-intermediary.jar:?]
at net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:723) ~[server-intermediary.jar:?]
at net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:270) ~[server-intermediary.jar:?]
at java.lang.Thread.run(Thread.java:833) [?:?]