The temperature on the Puck may be slightly different than the Temperature displayed in the Flair app.
The temperature displayed in the Flair app updates every five minutes, and shows the average room temperature. The temperature displayed on the Puck updates when the room temperature changes more than 1F. These update mechanisms are designed for conservative server usage. Most smart-home products operate in this manner.
If you're looking for exact temperatures, view the statistics. To view statistics for your entire home, tap the Flair menu and select "Home Statistics". To view statistics for a single room, tap the 3-dot menu on the room tile and select "stats".
If the temperature on the Puck does not represent the actual room temperature, you can calibrate the Puck. The best way to verify accurate room temperature is by comparing temperatures from at least two other temperature reading devices. If you're only comparing with one temperature reading device, it's hard to say which one is accurate.