I presume there's no chance of this being back ported to WatchOS 9.... some of my users will never update for various reasons including having an iPhone X stuck on iOS 16

This response made me chuckle! But yes I second that this happens quite a bit for me. Never on my development device without a passcode set, often on the other. Hopefully this might get fixed one day 🤞

iOS 15 so far seems to be the only fix

I've noticed this issue for several years now and never found any information or documentation on what's going on. Thank you very much for clarifying this. Any further information on what defines "older workout data", as in how old, specifically interested in heart rate. Tine to get on adopting HKQuantitySeriesSampleQuery!