Not so much in the league as in the Cup competitions. Even in the league we needed a good kick up the backside against WHU before we got back on track...it's just this feeling that unless we get into a pressure situation we don't really play to our optimum level. This up and down performance level spells doom for any league campaign where the primary objective is consistency. Sometimes dour, ugly, boring consistency.
Bayern at home aside, we've been horrendous in the CL, granted. Getting our backsides handed to us by Sheffield Wednesday was a wake-up call against complacency, but one which all the big teams have suffered in previous FA Cups and League Cups. Losing to West Ham may have been a catalyst for our later consistency, and to be fair to them they've been surprise giant slayers this season, so they deserve some kudos too.
I can compartmentalise the 2-0 loss against Chelsea for obvious reasons. Other than that, as you said, our league form can't be faulted. We're level on points with City, having won some tough fixtures more than convincingly. In any event, if it takes us being out of all cup competitions to finally win the title after 11 years, I'll take it.
Sometimes teams get momentum in one competition and go on to win it, while doing terribly in others. We did that last season, winning the FA Cup while having underachieving in the league, but other examples would be Liverpool winning the CL in 2005, and Wigan winning the FA Cup the same season that they got relegated.
In other words, I don't think there's good reason to worry that our inconsistency in the cup competitions might spill over into the league.