The icelandic sagas speak of "Skraelings" generically for all natives in the continent, though it is likely the Vinlanders encountered different peoples than the Greenlanders.

According to the Sagas, Leif spent one winter in Vinland. At first, half of their time was to be spent exploring, but after Tyrker the German found grapes, he cancelled that order. It's really not that strange that they found fruit before people.

What's slightly more peculiar is what happened with Thorvald. He went over a year without seeing anyone, but came across an abandoned shed. Then, when he first comes across natives, he immediately kills the majority and enslaves the others.

It's really purely speculation why that shed was abandoned, and why Thorvald didn't encounter any natives before. It's possible that the natives were presciently wary of these strangers. It's also possible that they just happened to have mostly left that area alone for unrelated reasons (e.g. the fishing was better elsewhere) years prior.