I just stumbled across a core file on summoner, badbod's server, which was created on February 18th. At this time the server was running 3.6.0.3. I do not know anything about what triggered it to be written, but at least we got a backtrace:
# gdb -q -n -ex bt -batch megaglest core.1646
[New Thread 1667]
[New Thread 1671]
[New Thread 1670]
[New Thread 1669]
[New Thread 1668]
[New Thread 1666]
[New Thread 1665]
[New Thread 1655]
[New Thread 1649]
[New Thread 1648]
[New Thread 1647]
[New Thread 1646]
warning: Can't read pathname for load map: Input/output error.
Can't read symbols from system-supplied DSO at 0x7fffd2dfd000: File truncated
Core was generated by `./megaglest --ini-path=./ --data-path=./ --headless-server-mode=vps,exit'.
Program terminated with signal 6, Aborted.
#0 0x00002ab21e0dbd05 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#0 0x00002ab21e0dbd05 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00002ab21e0dfab6 in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2 0x00002ab21d9c16dd in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3 0x00002ab21d9bf926 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#4 0x00002ab21d9bf953 in std::terminate() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#5 0x00002ab21d9bfa5e in __cxa_throw () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#6 0x00000000008a99c5 in Glest::Game::FactionThread::execute (this=0x2ab230014330) at /home/softcoder/Code/megaglest/branches/release-3.6.0.3/source/glest_game/type_instances/faction.cpp:359
#7 0x00000000009c3e9f in Shared::Platform::Thread::beginExecution (data=0x66e) at /home/softcoder/Code/megaglest/branches/release-3.6.0.3/source/shared_lib/sources/platform/sdl/thread.cpp:79
#8 0x00002ab21b44aa05 in ?? () from /usr/lib/libSDL-1.2.so.0
#9 0x00002ab21b48d649 in ?? () from /usr/lib/libSDL-1.2.so.0
#10 0x00002ab21b6d5d8c in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#11 0x00002ab21e18e04d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#12 0x0000000000000000 in ?? ()