Despite reports to the contrary, Isabel walked out before Shia LaBeouf's car crash. Our spies say right around Adrian's birthday (July 10), Isabel heard a female friend from out of town was coming to visit him. After this, Lucas was blunt ... him having "girl" friends was a deal breaker.

So she ditched him and he's been begging her to come back ever since! We're told Adrian made a play for Isabel after the accident, but she had nada interest in working things out.