Garmin Express keeps offering the 2.70 update for my FR220 even though it already has it. When I checked in the device listing it still shows the 220 on 2.60, even though it is definitely on 2.70
After removing the FR220 from GE and re-adding it, it correctly recognised the latest version was installed and now no longer offers the update.
So it seems GE is unable to update the device data when an update has been installed after the device was registered in GE.