Burst compiler fails when I try to use an external dll

In my project I'm using Jobs system for pathfinding. For the pathfinding I use an external dll for faster calculation. When I add [BurstCompile(CompileSynchronously = true)] to my job, the compiler gives an error saying;

Burst error BC0101: Unexpected error while processing function `GridPathfinding.Execute(GridPathfinding* this)`: System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.

Did anyone else encountered this?

 

Code (CSharp):

1.     public void Execute()
2.     {
3.         SimplePriorityQueue<HexCoordinates> frontier = new SimplePriorityQueue<HexCoordinates>();
4.         frontier.Enqueue(startingPoint, 0);
5.         HexCoordinates[] cellRefs = new HexCoordinates[cells.Length];
6.         cells.CopyTo(cellRefs);
7.  
8.         Dictionary<HexCoordinates, HexCoordinates> cameFrom = new Dictionary<HexCoordinates, HexCoordinates>();
9.         Dictionary<HexCoordinates, double> costSoFar = new Dictionary<HexCoordinates, double>();
10.  
11.         cameFrom[startingPoint] = startingPoint;
12.         costSoFar[startingPoint] = 0;
13.  
14.         while (frontier.Count > 0)
15.         {
16.             HexCoordinates current = frontier.Dequeue();
17.  
18.             if (current.Equals(destination))
19.             {
20.                 break;
21.             }
22.  
23.             foreach (HexCoordinates next in current.GetNeighbours())
24.             {
25.                 HexCoordinates nextRef = System.Array.Find(cellRefs, cell => cell.Equals(next));
26.                 double newCost = costSoFar[current]
27.                     + (nextRef.isTraversable ? 5 : 1);
28.                 if (!costSoFar.ContainsKey(nextRef)
29.                     || newCost < costSoFar[nextRef])
30.                 {
31.                     costSoFar[nextRef] = newCost;
32.                     double priority = newCost + GetCellDistance(nextRef, destination);
33.                     frontier.Enqueue(nextRef, (float)priority);
34.                     cameFrom[nextRef] = current;
35.                 }
36.             }
37.         }
38.  
39.         HexCoordinates currentPath = destination;
40.  
41.         int i = 0;
42.         while (!currentPath.Equals(startingPoint))
43.         {
44.             path[i] = currentPath;
45.             currentPath = cameFrom[currentPath];
46.             i++;
47.         }
48.  
49.         path[i] = startingPoint;
50.         pathLength[0] = i;
51.     }

As you can see it's a simple A* search. I'm using a commonly used Priority Queue from a dll. I watched using a debugger and It throw me an error when I instantiated SimplePriorityQueue.

 

It seems to have been fixed, strangely. I checked now and it seems to be working, I have updated my Unity a while ago so maybe it got patched. Still, thanks for the help!