This is SYNC 3, if my eyes don't deceive me, and I would bet a system reset would clear/fix that issue. If not, the next thing I'd try is to install a Sync update if one is available or even the same version if you still have a copy downloaded. I've not specifically had this happen for the Heat/Vent seats I have had it happen for other infotainment controls on my 21. The steps I would take to fix are:
1. Try forced reset by holding power and >> on radio at same time. If no luck then...
2. Use Forscan to hard reboot the APIM and IPC modules. If no luck then...
3. Reset back to factory. If no luck then...
4. Upgrade if available or reinstall same version if not of Sync via USB.
I kept every version of Sync that came out in case the new version changed something I didn't like and would downgrade. For those that feel a bit more tech inclined, you can also use CyanLabs Sync tool to install whatever version you may like but there are a few caveats. If you go CyanLabs route, make sure to follow all the warnings on "gotchas" otherwise it is safe and works well.