Oh, Fancy was trying! She really was. It’s tough when oil gets spilled. I have had the same experience. When you do spill oil (and it will likely happen again), abandon training for that day or at least move the game somewhere else completely.
Fancy showed some signs of frustration during that session and I’m curious to watch the next video but wanted to comment here first. When there is unexpected difficulty, it is good practice for you to find a way to manufacture some success. There are so many variables that come into play when the dog is truffle hunting and you won’t always know why they are having such a hard time in a specific scenario. If you can learn to gauge her frustration threshold, you can strategically manufacture a success before that point. By “manufacture a success” I mean, manipulate the environment so the dog has a successful find (for example, moving the scent to a more obvious place when the dog isn’t looking).
Another thing to consider…do you have any fans running in this area of your house? Always turn fans off when practicing. Otherwise the scent just moves all around the room and is very difficult to locate in an enclosed structure like a house.