You can try calling on Monday if you are able to get any further info from the call agent.
That being said it is obvious there are multiple old and new systems running at IRCC. Decision made is an approval. You generally don't get a refusal without some sort of additional document request e.t.c Also looks like your test was completed almost 2 months ago. Test invites are generally sent when most of the processing on your application is complete (for majority of applicants).
I know it would have been great for them to update the new system, but I do think this is very good news for you. Hopefully you will see the update on the new system as well and should be hearing in regards to the Oath soon.
Congrats! and best of luck! and keep us posted as you see any further updates.