Drowned

When zombies have armor on and turn to the Drowned they crash the server i run and every time the person near them logs back in it will re crash till the zombies despawn
this code is what it output on the server not sure if its what you are looking for

{16.03 04:27:58 [Server] Server thread/WARN Failed to load white-list: 
16.03 04:27:58 [Server] INFO com.google.gson.JsonParseException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 2 path $[0]
16.03 04:27:58 [Server] INFO at wi.a(SourceFile:507) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at wi.a(SourceFile:523) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at ut.g(SourceFile:145) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at ro.D(SourceFile:123) [minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at ro.<init>(SourceFile:30) [minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at rp.d(SourceFile:195) [minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at net.minecraft.server.MinecraftServer.run(SourceFile:502) [minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at java.lang.Thread.run(Thread.java:748) [?:1.8.0_152]
16.03 04:27:58 [Server] INFO Caused by: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 2 path $[0]
16.03 04:27:58 [Server] INFO at com.google.gson.stream.JsonReader.syntaxError(JsonReader.java:1559) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at com.google.gson.stream.JsonReader.checkLenient(JsonReader.java:1401) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at com.google.gson.stream.JsonReader.doPeek(JsonReader.java:593) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at com.google.gson.stream.JsonReader.hasNext(JsonReader.java:414) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:81) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO at wi.a(SourceFile:505) ~[minecraft_server.18w11a.jar:?]
16.03 04:27:58 [Server] INFO ... 7 more}