WiFi calling “for other devices” now inoperative after updating to iOS 13.6

Since updating my iPhone 8 and iPhone 8 Plus to iOS 13.6, I have lost the ability use WiFi Calling for other devices. Prior to this most recent iOS update, WiFi calling on iPads has been fully working.

Settings > Mobile Data > Wi-Fi Calling on This iPhone - set to ON

Settings > Mobile Data > Add Wi-Fi Calling For Other Devices - now unable to set to ON

Since this issue has occurred, iPads linked to iPhone (via Continuity) cannot make calls over WiFi - but must now be within close range of the host iPhone(s) to make a cellular call via the iPhone.

Prior to updating iPhones to iOS 13.6, WiFi Calling For Other Devices was enabled - and iPads were able to make calls independently of the iPhone over WiFi.

To clarify, I have two iPhones, each with a separate cellular account; each iPhone is signed-in to iCloud with a different AppleID as you would expect. Each iPhone has two iPads associated and signed-in to iCloud with the respective AppleID - each set-up, using Continuity features, to access Cellular Messaging and Calling features of the associated iPhone.

My Cellular carrier has since verified that nothing has changed; my Cellular plan is fully enabled for WiFi calling as before.

Can anyone verify that after updating to iOS 13.6 that they are experiencing similar issues with WiFi Calling with other devices?