Using `defaults` CLI when App Group is enabled : "domain does not exist"

I am developing a macOS app, with an embedded Finder Extension and I want the app and the extension to share UserDefaults

The App is Sandboxed for future distribution on the app store.

I followed instructions here : https://developer.apple.com/library/archive/documentation/General/Conceptual/ExtensibilityPG/ExtensionScenarios.html#//apple_ref/doc/uid/TP40014214-CH21-SW1

1. Both targets are part of the same app group, as it can be seen in the Entitlements:

    <key>com.apple.security.app-sandbox</key>
    <true/>
    <key>com.apple.security.application-groups</key>
    <array>
        <string>$(TeamIdentifierPrefix)com.stormacq.mac.MyApp</string>
    </array>
    <key>com.apple.security.files.user-selected.read-only</key>
    <true/>
   

2. I am accessing the UserDefaults by the suiteName :

   let defaults = UserDefaults.init(suiteName: "TEAM_ID.com.stormacq.mac.MyApp")
   
   //where TEAM_ID is the actual team id used to sign the app (something like 123AB45CDE)
   

However, when trying to read or write the defaults at App startup time, I receive this error message :

[User Defaults] Couldn't read values in CFPrefsPlistSource<0x600002c4d200> (Domain: TEAM_ID.com.stormacq.mac.MyApp, User: kCFPreferencesAnyUser, ByHost: Yes, Container: (null), Contents Need Refresh: Yes): Using kCFPreferencesAnyUser with a container is only allowed for System Containers, detaching from cfprefsd

I found weird that the error message says Container: (null),.

The group container and the shared Preference file is created (and contains the correct default values set by my code) :

➜  ~ ls -al ~/Library/Group\ Containers/TEAM_ID.com.stormacq.mac.MyApp/Library/Preferences/                                             
total 8
drwx------  3 stormacq  1896053708   96 Sep  6 19:58 .
drwx------  5 stormacq  1896053708  160 Sep  6 19:58 ..
-rw-------@ 1 stormacq  1896053708  103 Sep  6 19:58 TEAM_ID.com.stormacq.mac.MyApp.plist

# I edited TEAM_ID to post this message

I am using Xcode 11.7 (Swift 5) and macOS 10.15.6.

The shared preferences file is corrected created in ~/Library/Group Containers directory, but the defaults command line does not see it.

➜  ~ defaults read com.stormacq.mac.MyApp
2020-09-07 10:25:53.188 defaults[82827:947786] 
Domain com.stormacq.mac.MyApp does not exist

➜  ~ defaults read TEAM_ID.com.stormacq.mac.MyApp
2020-09-07 10:26:05.088 defaults[82857:947925] 
Domain TEAM_ID.com.stormacq.mac.MyApp does not exist

The same with non-shared preferences works correctly.

Can defaults read Group Containers ?