Found this: https://www.gpfans.com/en/f1-news/1020190/why-david-croft-not-commentating-imola-austria-azerbaijan-sky-sports-f1/

However, Croft's decision to step back for this and two upcoming races (Austria and Azerbaijan) is not a cause for concern."It's more about keeping fresh for the whole season," Croft explained in an interview with The Independent. "I'm not getting any younger." Croft also acknowledged the sacrifices he has made for his career, and wants to devote some time to his personal life, including his upcoming wedding to Laura Bradley, who is chief of guest services and hospitality at the Aston Martin F1 team.But beyond personal commitments, Croft sees this break as an opportunity to gain a fresh perspective."I also want to sit and watch a race at home," he continued.

Crofty took three weeks off. Why Brundle isn't there is something I don't understand.