Probably not a bug, but looking for a work around if possible.
just started using a smart ring (Ringconn) So far loving it and it does sync with Apple and Google fit, which in turns sends data to Interval. Everything is passed except HRV (RMSSD).
This will not happen unless there’s a native intervals.icu app on the iPhone. Apple health only works that way. And I believe google fit will also be that eventually. (Google fit is sunsetting. There’s a thread here as well)