Recently had an unexplained crash that seems related to how a pointer in the main tick thread is handled.  While this seems to be very rare in causing crashes, if this is related to an issue with pointers then I can see it recurring.

Dump:

Oct 14 11:08:46 server.address.removed bash[431]: [2020-10-14 11:08:46 INFO] Package: com.mojang.minecraft.dedicatedserver
Oct 14 11:08:46 server.address.removed bash[431]: Version: 1.16.40.2
Oct 14 11:08:46 server.address.removed bash[431]: OS: Linux
Oct 14 11:08:46 server.address.removed bash[431]: Server start: 2020-10-13 22:01:27 PDT
Oct 14 11:08:46 server.address.removed bash[431]: Dmp timestamp: 2020-10-14 11:08:46 PDT
Oct 14 11:08:46 server.address.removed bash[431]: Upload Date: 2020-10-14 11:08:46 PDT
Oct 14 11:08:46 server.address.removed bash[431]: Session ID: c7953ef7-5953-475c-80e6-1251991278cc
Oct 14 11:08:46 server.address.removed bash[431]: Commit hash:
Oct 14 11:08:46 server.address.removed bash[431]: Build id: development
Oct 14 11:08:46 server.address.removed bash[431]: CrashReporter Key: 8c4937c1-64cb-3532-a8dc-1deb28f67293
Oct 14 11:08:46 server.address.removed bash[431]: Crash
Oct 14 11:08:46 server.address.removed bash[431]: [2020-10-14 11:08:46 INFO] at std::__shared_ptr<MapItemTrackedActor, [__gnu_cxx::_Lock_policy]2>::get[] const (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at std::__shared_ptr_access<MapItemTrackedActor, [__gnu_cxx::_Lock_policy]2, false, false>::_M_get[] const (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at std::__shared_ptr_access<MapItemTrackedActor, [__gnu_cxx::_Lock_policy]2, false, false>::operator->[] const (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at MapItemSavedData::_findTrackedMapEntity[BlockPos const&] const (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at MapItemSavedData::getUpdatePacket[Level&, BlockPos const&] const (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at ItemFrameBlockActor::tick[BlockSource&] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at LevelChunk::tickBlockEntities[BlockSource&] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at LevelChunk::tick[BlockSource&, Tick const&] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at Player::tickWorld[Tick const&] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at ServerPlayer::tickWorld[Tick const&] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at std::function<bool [Player&]>::operator[][Player&] const (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at Level::forEachPlayer[std::function<bool [Player&]>] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at Level::tick[] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at ServerLevel::tick[] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at GameSession::tick[] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at Minecraft::tickSimtime[int, int] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at Minecraft::update[] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at ServerInstance::_update[] (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: at clone (UnknownFile:?)
Oct 14 11:08:46 server.address.removed bash[431]: 135754e4-58d3-4465-b0f2-6f7ad4637d75
Oct 14 11:08:46 server.address.removed systemd[1]: mcbe@ServerName.service: Main process exited, code=exited, status=1/FAILURE