To workaround this, delete information regarding deleted group from the security-policy.properties file... for instance:

**********************************************
group.test.home=HomePerspective
group.test.permission.asset.promote=false
group.test.permission.dataobject.edit=false
group.test.permission.editor.read=true
group.test.permission.editor.read.DMNDiagramEditor=false
group.test.permission.editor.read.GuidedDecisionTreeEditorPresenter=false
group.test.permission.editor.read.GuidedScoreCardEditor=false
group.test.permission.editor.read.ScenarioSimulationEditor=false
group.test.permission.editor.read.ScoreCardXLSEditor=false
...
**********************************************
Save the file and then commit the change ... :

***********************************************
[user@user authz]$ cd ..
[user@user security]$ git add --all
[user@user security]$ git commit -m "Edit security-policy.properties file"
[user@user security]$ git push --force
***********************************************

Finally, restart the server.

1. Log in to Business Central UI as admin user and create a completely new group (use the name that hasn't been used before);
2. Confirm that this group will have disabled all permissions for "Pages" by default;
3. Change some permissions for this group and save the change (this can be done only by enabling "Read" permission for "Pages");
4. Delete this group from Business Central;
5. Navigate to $RHPAM_HOME/bin/.niogit/system;
6. Perform:
*****************************
git clone security.git
*****************************
7. Navigate to: security/authz, open security-policy.properties file and confirm that previously deleted group still exists in this file.

This is why, when again a new group is created using the same name as the group that was deleted, it will have all the permissions enabled as the old group.