Cannot ride Horse on LAN

When riding a horse on a lan world, it crashes with a NullPointerException. After that, can no longer connect to that lan world.

Client> java.lang.NullPointerException
Client> at ek.n(SourceFile:174)
Client> at ck.a(SourceFile:237)
Client> at ck.a(SourceFile:225)
Client> at ck.h(SourceFile:175)
Client> at ck.d(SourceFile:16)
Client> at cm.run(SourceFile:115)