What are the ramifications of disclosing information during preliminary negotiations?

Q. A recently terminated employee retained an attorney, who then engaged in pre-suit negotiations with our HR vice president. During those negotiations, our VP disclosed, in writing, some confidential information about the internal investigation that led to this employee’s termination. Negotiations have since broken down and the employee filed suit. Should I be concerned about these pre-suit disclosures coming back to haunt us in the litigation?