I first tried clearing Moto Mods Manager Data and wiping System Cache. No Change.
I then bit the bullet and did a factory reset.
I powered on the phone and chose not to restore my account. Once the phone was booted to the desktop (with no added software installed) I attached the Wireless Charging Style Shell and received the "The Moto Mod isn't lined up correctly. Make sure the connector is clean and try attaching again" message, ARGH!
The phone will NOT wirelessly charge, USB-C connector charging works just fine.
Before the Oreo Update, I would get the "The Moto Mod isn't lined up correctly. Make sure the connector is clean and try attaching again." message but the phone would still charge with the wireless style shell. After the Oreo update I get the message, but the phone does NOT charge. So I may have had a hardware problem all along, but for whatever reason the wireless charging style shell worked until the Oreo update.
So it's looking more and more like there is a hardware issue.
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Michael