For me it successfully changes the Flair “set point” for the room, so it seems to work ok.
A couple more thoughts on what I posted above:
Flair seems to struggle to detect when to switch between cool and heat mode with ecobee. Today I left Flair in heat/cool mode, but even after the AC had been running for a while, the set points were still using the old heating set point. I then manually set Flair to cool mode, and nothing changed, it still was using the heat set point (that technically doesn’t even exist any more, since the ecobee was in cool mode). Finally, I set Flair to manual and adjusted some vents, then went in an hour or so later and set it to cool mode again, and it then pulled the correct set point from the ecobee. Something flaky going on there for sure.