Whenever I update to RB 1060, no one can log in

logged in with entity id 1443 at ([world] -4203.699999988079, 75.0, 4162.300000011921)
22:29:40 [SEVERE] java.lang.NullPointerException
22:29:40 [SEVERE] at java.lang.System.arraycopy(Native Method)
22:29:40 [SEVERE] at java.io.BufferedOutputStream.write(BufferedOutputStream.java:111)
22:29:40 [SEVERE] at java.io.DataOutputStream.write(DataOutputStream.java:90)
22:29:40 [SEVERE] at net.minecraft.server.Packet51MapChunk.a(Packet51MapChunk.java:88)
22:29:40 [SEVERE] at net.minecraft.server.Packet.a(Packet.java:116)
22:29:40 [SEVERE] at net.minecraft.server.NetworkManager.f(NetworkManager.java:107)
22:29:40 [SEVERE] at net.minecraft.server.NetworkManager.d(NetworkManager.java:263)
22:29:40 [SEVERE] at net.minecraft.server.NetworkWriterThread.run(SourceFile:107)
22:29:40 [INFO] Connection reset



Whenever someone tries to log in, that error is what shows up in the console.
For some reason this only occurs with build 1060. With build 1000, this error does not occur.

Any help is much appreciated.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.