That looks like over 20% crystal malt. That may not be the issue, but that's what sticks out to me.
Also, check mrmalty.com and look at the "yeast pitching calculator" to make sure you're pitching the correct amount of yeast. I suspect there is something with the yeast health. With an OG of 1.054, and yeast dated from one month ago, the correct starter size would be 2.65 liters.
Broken Leg Brewery
Giving beer a leg to stand on since 2006