We're at a bit of a disadvantage in that the person who submitted this recipe has been absent from the forum for quite a time, so we can't turn to her for advice. Looking at the recipe, one thing stands out. There's no mention of browning the chicken before adding all the ingredients, which I find a bit odd. Since you're already using thin chicken breast, it shouldn't take too long to cook, so perhaps quickly browning it after sprinkling with the seasonings may help the issue.