We had a delay of 1 week due the construction strike. But we receive a notice i think 3 month before. This change has no effect on us since the date was changed from 20th to 27th and our lease ends the 31th.
To be safe i suggest you to keep your lease until end of august. This way you also don't rush you moving. In regards of our experience with phase 2b, the hole think was good. Very pleased with the quality and the customer service.