A participant is working after normal retirement. Their accrued benefit is limited by 415 salary cap.

They have not taken the retirement benefit that was payable at normal retirement.
An actuarial increase for late retirement is not available.

If they continue work and receive higher pay to justify a new limit, then the facts change and an increase is permitted.

I believe they should receive a notice of suspension of benefits, because they permanently lose
the right to take that payment.