Confirming that I received the same email stating the March 18th date for decisions to be communicated, but I too have not received an additional email with any decision.
It sounds as if this year's prospective cohorts have had a much higher number of applicants than in the past. I'm very sympathetic to the admissions teams, but it's unfortunate to have an expectation communicated with no follow-through, or follow-up stating that the date needs to be pushed further out.
The veiled and long timelines for these processes to play out has added unnecessary pressure to an already stressful situation. I wish there was a more unified approach, like a Match Day, or something similar.