Mailing List sync not Saved and therefore New Mailing List members don't synchronize to Google Contacts

[martinsydsin]

It's great to have GContactSync working again under TB 68! Thank you to everyone who has contributed to getting this great add-on back to life!

I noticed that GCS seems to ignore new members of mailing lists when syncing to Google Contacts.

To Reproduce
Add an existing contact to a TB Address book mailing list.
Sync
Sync log shows no updates

Upon checking the account details I noticed that only the default groups were listed under "Groups and Contacts to sync"
Finding all groups resulted in listing all groups but this does not seem to save. After saving and closing (and restarting or not restarting TB) and opening the account details again it reverted back to the default account groups. Default groups save to Google but non-default groups do not.

Expected behavior
When saving account preferences with all mailing lists to sync this should remain a stored preference.
New mailing list members should be synced to and label should be added in Google Contacts

Maybe there is some workaround that the mailing lists to be synced can be manually added to a configuration file?

Desktop (please complete the following information):
Win 10
GCS 3.2.0
TB 68.9.0

Additional context
Add any other context about the problem here.

[martinsydsin]

Brief update

After some more testing I found that deletions from mailing lists sync to Google even though the non-standard groups don't show up in the Accounts Drop down list.

Adding contacts to a mailing list does not trigger an update though. Any sync after a contact has been added to a mailing list shows 0 Updates.

[martinsydsin]

Further update after some more testing
Deleting contacts from mailing triggers an update. But the actual update only occurs if the contact to be deleted from the mailing list has a email address in Google. If the email address in the contact is a "generated" email address if will not remove the label in Google.