If someone was to tell you an improbable story while you know they can't lie then it's truthful.

But if that person turns out later to be able to lie, what makes you think it was truth.

If she was searching them out all it means is that she knew them to be in the general area and had a message for them. whichever one she could find. It doesn't mean her inn caught fire, her bed had fleas or whatever it was she said. Making up something like that and attributing it to ta'vern is just an easy way out to explain her meddling.