I've seen discussions elsewhere dating 3 years ago.
I've just bought a Tempe to track temperature while running and hiking. I couldn't believe Garmin data filtering is so basic.
As you can see from the graph, it sometimes doesn't get any measurement from the Tempe sensor, thus reverting to the internal (useless) one.
How difficult is to understand that if 99% of the measurements come from the external sensor, even if a measurement is missing it should just duplicate the previous one, not creating a spike?
(note that the screenshot is from the iOS app, but this is the same for web)