I don't know. I saw that Vancouver game as the beginning of the Spiral, IMO. It wasn't a straight plummet, but it slowly began picking up speed as the season bore on. It was the first game to really set off all my alarm bells.
For the most part they played well in January (10 wins) but they had probably two unsettling loses to Boston and New Jersey.
The Boston game was a facepalm I think the final score was 5-4...the only goal I remember was the Marchand goal when Boston should have been penalized for a 'delay of game' but the refs never called it, and instead of backchecking the Flyers (*ahem* Briere) decided to use that time to complain to the refs while Marchand scored
The New Jersey game however was a complete.suck.fest.
There wasn't really much to complain about in January (like I said we won 10 games) but I can see where you're coming from. For me, that Vancouver game marked the first time that I felt the Flyers probably weren't as good as I thought they were. It was also the first time I felt they weren't going to win the Stanley Cup.