Employee vs. Employer Contributions
In 401(k) plans, account balances often include money the employee contributed (which is usually 100% vested) and employer matching or profit-sharing contributions (which may be subject to a vesting schedule). If only some of the employer contributions are vested at the time of divorce, the QDRO needs to define what’s being divided—just the vested amount or the full account.
If you don’t account for this clearly, the alternate payee could end up with less than expected—or the participant could owe more than intended.

