Employee and Employer Contributions
Employee contributions are always fully vested—those belong entirely to the participant once withheld from their paycheck. However, employer contributions usually follow a vesting schedule. In some cases, the employee must work for the company a certain number of years before they own 100% of these contributions.
Your QDRO must account for any unvested portion at the time of divorce or division. If you don’t, you could unintentionally assign money that may never become available to divide.

