Doesn't surprise me. Despite this riding having always voted Liberal since its creation in 1966 (and before that since 1952), the Liberals have rarely broken 45% in recent years. Now with an alternative right-of-centre non-separatist party, federalist voters can shop around.
It's not really a particularly federalist riding (relatively speaking); it was only 52% Non, and nearly voted PQ in both 1994 and 1998. Which makes a CAQ victory even less surprising; the issue in the past seems to be that the PQ retained a lot of residual strength and organization even when they weren't in a position to potentially win (e.g., the PQ were still a solid second in 2007 over the ADQ in distant third despite the ADQ knocking the PQ into third province-wide).
