Hi Chris,
I would be tempted to go back to the working version SCCP70-8-2-1S at least on a temporary basis. You will need to upgrade before mid October to avoid any DST related issues with this Firmware but at least it would solve this initial problem.
On the Phone Configuration page for the one "oddball" 7970 have a look at the **setting which has probably prevented this phone from using the SCCP70-8-2-2SR4S.
**Firmware Load Information (leave blank to use default)
Phone Load Name (probably has something like SCCP70-8-2-1S)
SCCP70-8-2-2SR4S is probably set on the Device Default page in CCM and is why the other phones have upgraded to this Firmware.
If you go to the Device Default page in CCM Admin you can tag the phones to use the older Firmware. Once the phones are booted they will downgrade to the older version.
Hope this helps! And makes some sense.
Rob