Same situation here. St.Catharines applicant tested at Scarborough and DM immediately next day.Congratulations!!
My test was also done in Scarborough and status changed to DM the next day however I'm still waiting for the oath invite. Called IRCC last week and they told me they will notify me "as soon as there is a spot open in Scarborough". I think there are also lots of people waiting for oath invites from Scarborough office. It's interesting that they have spots for people took tests later than us. Wondering what is going on.
During the interview was asked to get my file transferred to Niagara Falls as Scarborough doesn't have slots in the near future.
Today I see oath ceremonies in St.Catharines 1 in March and April each and 2 in May. So dont know what will be the venue for me, Scarborough, Niagara Falls, St.Catharines or SURPRISE!!