Program: 27588
Project: 27588
Buggy source:
@Overwrite public void wakeUpPlayer(boolean immediately,boolean updateWorldFlag,boolean setSpawn){
  IBlockState iblockstate=this.nmsPlayer.worldObj.getBlockState(this.playerLocation);
  Transform<World> newLocation=null;
  if (this.playerLocation != null && iblockstate.getBlock().isBed(this.nmsPlayer.worldObj,this.playerLocation,this.nmsPlayer)) {
    iblockstate.getBlock().setBedOccupied(this.nmsPlayer.worldObj,this.playerLocation,this.nmsPlayer,false);
    BlockPos blockpos=iblockstate.getBlock().getBedSpawnPosition(this.nmsPlayer.worldObj,this.playerLocation,this.nmsPlayer);
    if (blockpos == null) {
      blockpos=this.nmsPlayer.playerLocation.up();
    }
    newLocation=this.getTransform().setPosition(new Vector3d(blockpos.getX() + 0.5F,blockpos.getY() + 0.1F,blockpos.getZ() + 0.5F));
  }
  SleepingEvent.Post post=null;
  if (!this.nmsPlayer.worldObj.isRemote) {
    post=SpongeEventFactory.createSleepingEventPost(Sponge.getGame(),Cause.of(NamedCause.source(this)),this.getWorld().createSnapshot(VecHelper.toVector(this.playerLocation)),Optional.ofNullable(newLocation),this,setSpawn);
    Sponge.getEventManager().post(post);
    if (post.isCancelled()) {
      return;
    }
    net.minecraftforge.event.ForgeEventFactory.onPlayerWakeup(this.nmsPlayer,immediately,updateWorldFlag,setSpawn);
    this.setSize(0.6F,1.8F);
    if (post.getSpawnTransform().isPresent()) {
      this.setTransform(post.getSpawnTransform().get());
    }
  }
  this.sleeping=false;
  if (!this.nmsPlayer.worldObj.isRemote && updateWorldFlag) {
    this.nmsPlayer.worldObj.updateAllPlayersSleepingFlag();
  }
  this.sleepTimer=immediately ? 0 : 100;
  if (post != null) {
    if (setSpawn) {
      this.setSpawnPoint(post.getSpawnTransform().isPresent() ? VecHelper.toBlockPos(post.getSpawnTransform().get().getPosition()) : this.playerLocation,false);
    }
    Sponge.getGame().getEventManager().post(SpongeEventFactory.createSleepingEventFinish(Sponge.getGame(),post.getCause(),this.getWorld().createSnapshot(VecHelper.toVector(this.playerLocation)),this));
  }
 else {
    if (setSpawn) {
      this.setSpawnPoint(this.playerLocation,false);
    }
  }
}

Fixed version (ground truth):
@Overwrite public void wakeUpPlayer(boolean immediately,boolean updateWorldFlag,boolean setSpawn){
  IBlockState iblockstate=this.nmsPlayer.worldObj.getBlockState(this.playerLocation);
  Transform<World> newLocation=null;
  if (this.playerLocation != null && iblockstate.getBlock().isBed(this.nmsPlayer.worldObj,this.playerLocation,this.nmsPlayer)) {
    iblockstate.getBlock().setBedOccupied(this.nmsPlayer.worldObj,this.playerLocation,this.nmsPlayer,false);
    BlockPos blockpos=iblockstate.getBlock().getBedSpawnPosition(this.nmsPlayer.worldObj,this.playerLocation,this.nmsPlayer);
    if (blockpos == null) {
      blockpos=this.nmsPlayer.playerLocation.up();
    }
    newLocation=this.getTransform().setPosition(new Vector3d(blockpos.getX() + 0.5F,blockpos.getY() + 0.1F,blockpos.getZ() + 0.5F));
  }
  SleepingEvent.Post post=null;
  if (!this.nmsPlayer.worldObj.isRemote) {
    post=SpongeEventFactory.createSleepingEventPost(Sponge.getGame(),Cause.of(NamedCause.source(this)),this.getWorld().createSnapshot(VecHelper.toVector(this.playerLocation)),Optional.ofNullable(newLocation),this,setSpawn);
    Sponge.getEventManager().post(post);
    if (post.isCancelled()) {
      return;
    }
    net.minecraftforge.event.ForgeEventFactory.onPlayerWakeup(this.nmsPlayer,immediately,updateWorldFlag,setSpawn);
    this.setSize(0.6F,1.8F);
    if (post.getSpawnTransform().isPresent()) {
      this.setTransform(post.getSpawnTransform().get());
    }
  }
 else {
    net.minecraftforge.event.ForgeEventFactory.onPlayerWakeup(this.nmsPlayer,immediately,updateWorldFlag,setSpawn);
    this.setSize(0.6F,1.8F);
  }
  this.sleeping=false;
  if (!this.nmsPlayer.worldObj.isRemote && updateWorldFlag) {
    this.nmsPlayer.worldObj.updateAllPlayersSleepingFlag();
  }
  this.sleepTimer=immediately ? 0 : 100;
  if (post != null) {
    if (setSpawn) {
      this.setSpawnPoint(post.getSpawnTransform().isPresent() ? VecHelper.toBlockPos(post.getSpawnTransform().get().getPosition()) : this.playerLocation,false);
    }
    Sponge.getGame().getEventManager().post(SpongeEventFactory.createSleepingEventFinish(Sponge.getGame(),post.getCause(),this.getWorld().createSnapshot(VecHelper.toVector(this.playerLocation)),this));
  }
 else {
    if (setSpawn) {
      this.setSpawnPoint(this.playerLocation,false);
    }
  }
}