As part of the change from GOES to TTP, CBP is now enforcing a 365-day maximum limit by which the applicant must actually interview (and provide follow-up documents about criminal charges, etc.?) after receiving conditional approval.

Previously, as long as the applicant used the interview scheduling tool within 120 days of receiving conditional approval, they could continuously reschedule, presumably out into eternity.

The 120-day limit for first picking a date seems to have been eliminated.

More discussion is here:

Significant changes/additions in GE, NEXUS, SENTRI app procedures with new TTP site