Why can't I see the Microsoft Teams Meeting add-in for Outlook?

I am running 32-bit Office.  If I install 64-bit Teams as a standard user, the Teams Meetings add-on fails to install.  This is the log from %LOCALAPPDATA%\Microsoft\Teams\TeamsMeetingAddin:

2019-01-23-05:38:03.145 PM System.ArgumentException: Cannot delete a subkey tree because the subkey does not exist.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at Microsoft.Win32.RegistryKey.DeleteSubKeyTree(String subkey, Boolean throwOnMissingSubKey)
   at Microsoft.Win32.RegistryKey.DeleteSubKeyTree(String subkey)
   at Squirrel.MeetingAddinInstaller.<InstallMeetingAddinAsync>d__14.MoveNext()
2019-01-23-05:38:03.153 PM StagedAppDirectory does not exist. Using Current
2019-01-23-05:38:03.153 PM Version: 1.0.18317.2; addinPackageDirectory: 1.0.18317.2
2019-01-23-05:38:03.155 PM .dead exists: False
2019-01-23-05:38:03.155 PM before cleanup unused versions
2019-01-23-05:38:05.801 PM Addin directory exists. Copy was successful
2019-01-23-05:38:25.648 PM Failed to install the Teams meeting add-inCOM registration failed. Regsvr Path: C:\WINDOWS\system32\regsvr32.exe, Arguments: /s /n /i:user "C:\Users\rbz\AppData\Local\Microsoft\TeamsMeetingAddin\1.0.18317.2\x64\Microsoft.Teams.AddinLoader.dll", ErrorCode: 0, % Message: 
2019-01-23-05:38:25.649 PM Directory exists. deleting...
2019-01-23-05:38:25.650 PM x64 Directory exists. deleting...
2019-01-23-05:38:25.651 PM x86 Directory exists. deleting...

It successfully copies the files but attempts to register the x64 add-in and fails.

I uninstalled 64-bit Teams and installed 32-bit Teams (matching the version of Office I am using), but it fails again as it attempts to register the x64 add-in.

Why is it attempting to register (and fails) the 64-bit add-in for my 32-bit Office?  I haven't tried uninstalling my 32-bit Office and installing 64-bit Office and seeing what happens when I install 32-bit and 64-bit Teams.