Breathing Variations Detection Issue

My recently purchased FR 970's breathing variations detection varies, some mornings I see the data in sleep page but on others, it does not detect and generate data at all. Although Pulse OX is on and generating data regularly, this morning I noticed that although I see a reading value for Pulse OX on my watch, I don't see it in Garmin Connect app (see the attached screen shot) Any idea why? 

Garmin Connect screen shot as of 9 July 2025