Broadway Flash said: "Fred Lassen is taking over as MD after opening. I guess the British guy isn’t staying in ny."
If true, this is completely normal, especially for a Brit who has to be housed by the production.
Not to digress here, but...
The big to-do in Broadway musicworld nowadays is that nobody wants to do 8 shows a week if you can do less. It's becoming unusual for the major names in Broadway music departments to actually conduct a Broadway run with regularity. They take on the Music Supervisor title, they're liaison between the composer and the rest of the music dept, they run rehearsals, they supervise everything during tech and previews, they oversee cleanup rehearsals, they make the major decisions, but they let someone else conduct it.
It's one of those things that makes costs go up, too, because now there's a Music Supervisor fee and a separate Music Director fee (which are both separate fees from the Conductor, arrangers, orchestrator, etc). When the Music Director and Conductor role used to be the same person, and the Music Supervisor role didn't even exist until well into a run when other companies and replacements started happening.