blight portal spawned in the ore unable to complete

So apparently if you run a blight that extremely close to a ore deposit there's a rare chance where the portal spawn in the ore and you can't complete it because the monster are stuck this has happened twice now and it might happen more in the future is there a way to fix this or is it (it is what it is) situation?

I had same problem several times already. Sometimes I dont even start blight near the deposits cos this happening too often.