How'd you carbonate?
I have nearly the exact same thread going on now (but different line lengths, psi, and temp) and its been suggested that my beer is overcarbed. (I burst carbed by rocking/rolling @ serving pressure, then set it to 20psi for about a day before returning to serving pressure)
from reading, an overcarbed beer will come out flat and foamy due to co2 coming out of suspension when you pour.
Brewing Since July 2012 Extract, and All-grain BIAB
Primary 1: BM Centennial Blonde (again :) )
Primary 2: Raging Irish Red
Secondary 1: Skeeter Pee
Secondary 2: Air
Bottled/Kegged: Apfelwein, Two Hearted Clone, Graff