I'm not 100% sure with the admission process, but this is my guess.
They first carefully review PhD applicants by reading through their CVs, researches, GPAs, etc.
Then they select which PhD applicants should get funding.
Those who were at borderline were offered MS.
I just saw the result section that a lot of people are getting rejections today.
Then, after dealing with PhD applicants, they review MS applicants (maybe starting last week or this week).
For MS, funding is not provided, so they don't have to be extremely selective. ( Maybe now this phase?)
By the end of next week, the decisions will be released based on their admission timeline page.