I checked the full Brandon Aiyuk page in the wiki (which covers his contract limbo, reinstatement status, and potential landing spots like Washington, Atlanta, and Las Vegas), but there's no mention of him firing his agent or terminating his SRA. That specific detail isn't something the wiki has tracked.
It's possible this happened before the 2026 season's coverage window or came from a source that wasn't ingested. You might want to check social media or recent NFL news aggregators for that one.