I just received confirmation from Polycom that the patch that was pushed out to OBiTALK 200 series ATAs today is to fix the one-way-audio issue. Since I never experienced it myself, I can't confirm it fixes everything for everyone, but if you have removed your device(s) from the OBiTALK portal, add them back to get the patch.
There is no point to fiddling with the various System Management-->Auto Firmware Update settings. As long as the device is added to the portal, it should get the update. Note that the default OBiTALK setting for Auto Firmware Update is "Disabled", with no firmware URL specified. The device will still receive the new firmware. The rest of the settings on the System Management page are for service-provider-managed devices only (e.g. for businesses that use devices provided by and managed by an ITSP).
The patched build is 3.2.2 (Build: 5898EX)