Enderman glitch death

Apparently one of the players on my server experienced a glitch-death at the hands of an enderman. This stack trace was dumped to the console at the same time.

Wrong location! pm['Enderman'/489601, l='swim2', x=-149.35, y=44.17, z=-17.65]
java.lang.Exception: Stack trace
        at java.lang.Thread.dumpStack(Thread.java:1342)
        at za.a(SourceFile:508)
        at zn.a(SourceFile:277)
        at zn.a(SourceFile:87)
        at zn.a(SourceFile:75)
        at id.f(SourceFile:111)
        at id.c(SourceFile:73)
        at ic.<init>(SourceFile:26)
        at ib.a(SourceFile:171)
        at ib.d(SourceFile:299)
        at ge.d(SourceFile:147)
        at im.a(SourceFile:295)
        at dt.a(SourceFile:136)
        at bx.b(SourceFile:341)
        at im.d(SourceFile:73)
        at in.b(SourceFile:35)
        at hk.b(SourceFile:30)
        at net.minecraft.server.MinecraftServer.r(SourceFile:731)
        at hg.r(SourceFile:233)
        at net.minecraft.server.MinecraftServer.q(SourceFile:661)
        at net.minecraft.server.MinecraftServer.run(SourceFile:595)
        at fp.run(SourceFile:818)