Program: 156312
Project: 156312
Buggy source:
@Override public void update(){
  if (world.isRemote) {
    prevClientDrillPos=clientDrillPos;
    clientDrillPos=drillPos;
    if (currentTask != null) {
      currentTask.clientTick();
    }
    return;
  }
  if (!frameBox.isInitialized() || !miningBox.isInitialized()) {
    return;
  }
  if (!toCheck.isEmpty()) {
    for (int i=0; i < (firstChecked ? 10 : 50); i++) {
      BlockPos blockPos=toCheck.pollFirst();
      check(blockPos);
      toCheck.addLast(blockPos);
    }
  }
  if (currentTask != null) {
    long max=MAX_MJ_PER_TICK;
    max*=battery.getStored() + max;
    max/=battery.getCapacity() / 2;
    max=Math.min(max,MAX_MJ_PER_TICK);
    long power=battery.extractPower(0,max);
    if (currentTask.addPower(power)) {
      currentTask=null;
    }
    sendNetworkUpdate(NET_RENDER_DATA);
    return;
  }
  if (!firstChecked) {
    return;
  }
  if (!frameBreakBlockPoses.isEmpty()) {
    BlockPos blockPos=frameBreakBlockPoses.iterator().next();
    if (!canNotMine(blockPos)) {
      drillPos=null;
      currentTask=new TaskBreakBlock(blockPos);
      sendNetworkUpdate(NET_RENDER_DATA);
    }
    check(blockPos);
    return;
  }
  if (!framePlaceFramePoses.isEmpty()) {
    for (    BlockPos blockPos : getFramePositions()) {
      if (!framePlaceFramePoses.contains(blockPos)) {
        continue;
      }
      check(blockPos);
      if (!framePlaceFramePoses.contains(blockPos)) {
        continue;
      }
      drillPos=null;
      currentTask=new TaskAddFrame(blockPos);
      sendNetworkUpdate(NET_RENDER_DATA);
      return;
    }
  }
  if (boxIterator == null || drillPos == null) {
    boxIterator=createBoxIterator();
    while (world.isAirBlock(boxIterator.getCurrent()) || canSkip(boxIterator.getCurrent())) {
      if (boxIterator.advance() == null) {
        break;
      }
    }
    drillPos=new Vec3d(miningBox.closestInsideTo(pos));
  }
  if (boxIterator != null && boxIterator.hasNext()) {
    boolean found=false;
    if (drillPos.squareDistanceTo(new Vec3d(boxIterator.getCurrent())) >= 1) {
      currentTask=new TaskMoveDrill(drillPos,new Vec3d(boxIterator.getCurrent()));
      found=true;
    }
 else     if (!world.isAirBlock(boxIterator.getCurrent()) && !canSkip(boxIterator.getCurrent())) {
      if (!canNotMine(boxIterator.getCurrent())) {
        currentTask=new TaskBreakBlock(boxIterator.getCurrent());
        found=true;
      }
    }
 else {
      found=true;
      BlockPos next=boxIterator.advance();
      if (next == null) {
        currentTask=null;
      }
 else {
        currentTask=new TaskMoveDrill(drillPos,new Vec3d(next));
      }
    }
    if (found) {
      sendNetworkUpdate(NET_RENDER_DATA);
    }
  }
}

Fixed version (ground truth):
@Override public void update(){
  if (world.isRemote) {
    prevClientDrillPos=clientDrillPos;
    clientDrillPos=drillPos;
    if (currentTask != null) {
      currentTask.clientTick();
    }
    return;
  }
  if (!frameBox.isInitialized() || !miningBox.isInitialized()) {
    return;
  }
  if (!toCheck.isEmpty()) {
    for (int i=0; i < (firstChecked ? 10 : 50); i++) {
      BlockPos blockPos=toCheck.pollFirst();
      check(blockPos);
      toCheck.addLast(blockPos);
    }
  }
  if (currentTask != null) {
    long max=MAX_MJ_PER_TICK;
    max*=battery.getStored() + max;
    max/=battery.getCapacity() / 2;
    max=Math.min(max,MAX_MJ_PER_TICK);
    debugPowerRate=max;
    long power=battery.extractPower(0,max);
    if (currentTask.addPower(power)) {
      currentTask=null;
    }
    sendNetworkUpdate(NET_RENDER_DATA);
    return;
  }
  if (!firstChecked) {
    return;
  }
  if (!frameBreakBlockPoses.isEmpty()) {
    BlockPos blockPos=frameBreakBlockPoses.iterator().next();
    if (!canNotMine(blockPos)) {
      drillPos=null;
      currentTask=new TaskBreakBlock(blockPos);
      sendNetworkUpdate(NET_RENDER_DATA);
    }
    check(blockPos);
    return;
  }
  if (!framePlaceFramePoses.isEmpty()) {
    for (    BlockPos blockPos : getFramePositions()) {
      if (!framePlaceFramePoses.contains(blockPos)) {
        continue;
      }
      check(blockPos);
      if (!framePlaceFramePoses.contains(blockPos)) {
        continue;
      }
      drillPos=null;
      currentTask=new TaskAddFrame(blockPos);
      sendNetworkUpdate(NET_RENDER_DATA);
      return;
    }
  }
  if (boxIterator == null || drillPos == null) {
    boxIterator=createBoxIterator();
    while (world.isAirBlock(boxIterator.getCurrent()) || canSkip(boxIterator.getCurrent())) {
      if (boxIterator.advance() == null) {
        break;
      }
    }
    drillPos=new Vec3d(miningBox.closestInsideTo(pos));
  }
  if (boxIterator != null && boxIterator.hasNext()) {
    boolean found=false;
    if (drillPos.squareDistanceTo(new Vec3d(boxIterator.getCurrent())) >= 1) {
      currentTask=new TaskMoveDrill(drillPos,new Vec3d(boxIterator.getCurrent()));
      found=true;
    }
 else     if (!world.isAirBlock(boxIterator.getCurrent()) && !canSkip(boxIterator.getCurrent())) {
      if (!canNotMine(boxIterator.getCurrent())) {
        currentTask=new TaskBreakBlock(boxIterator.getCurrent());
        found=true;
      }
    }
 else {
      found=true;
      BlockPos next=boxIterator.advance();
      if (next == null) {
        currentTask=null;
      }
 else {
        currentTask=new TaskMoveDrill(drillPos,new Vec3d(next));
      }
    }
    if (found) {
      sendNetworkUpdate(NET_RENDER_DATA);
    }
  }
}