On many websites, including his own, Carsten Morar-Haffke is only listed as Carsten Haffke. I'm in favor of changing the name of his wiki page. I've done that before, but somebody changed it again. What do you think, should we change the name of his wiki page to "Carsten Haffke"?
I'm not sure he is credited on Sesamstrasse (which often has few on-screen credits, although that may have changed now; they put most of the performer names and bios on the website instead). But he is on the assorted spin-offs and specials. Here's a screengrab I took of the credits for Der Schatz des Käpt'n Karotte. He's credited as Morar-Haffke there (and most likely, on the others).
Looking at older NDR and Studio Hamburg press releases/bios and more recent ones it's a situation where they made a change later on to how they wanted billing (it's even noted in the history when someone who works on the show made the change in 2010; the official 40th anniversary presskit from 2012 also lists him as Morar-Haffke, as has at least one downloadable resume). Assorted voice agency sites also list him as Morar-Haffke. On his official site, the 2018 copyright at the very bottom is to "Carsten-Morar Haffke" (which is the only place to put the hyphen there, so likely just a typo, since another sentence in the same copyright passage uses Carsten Morar-Haffke).