The 5-7-storey cladding lag thing is a pretty common trope that I hear a lot from old school construction folks, or from folks who’ve picked that up from old school construction folks. It takes one look around almost any site in the city to see that this fairly rarely occurs.
There are also reasons why you’d either choose or be forced to delay cladding, and one can’t really intuit what those might be without direct knowledge of a project, nor if they have an impact on occupancy (which is really all that matters).