I am in same boat , Had my test on Feb 26 , e-cas changed to DM next day but haven't heard anything .Not sure what is happening with the Edmonton Office. I completed successfully my test Feb 13, 2018. My eCas changed to Decision Made next day... But nothing has changed since then. I didn’t expect it would take so long to get the Oath invitation letter after the test. This waiting time without a reason is very frustrating.