That is great, and the exact right thing to do. You always want to encourage sucess- and not suprising that Lola didn’t key in on it. Thus far she has notr been asked to check for scent coming out of the ground. There also can be a myriad of factors as to why an odor may not penetrate above the soil. That is why you pratice in as many varied situations as possible.
That is perfectly fine– and in fact even ideal for your situation. She does her passive alert at a distance when she detects odor which works well with your other nosework classes and then with the “show me” cue she has associated that with actually retrieving the truffle. That is very good. You will want to encourage her and praise when she passive alerts but not reward until after she has showed you.
As you practice Nosework with her passive alert that behavior will still be reinforced- so you’re in great shape.