Are you running the RX clutched rear derailleur? If so, could that be the culprit? I ask because I'm running Ultegra 6800 with the Absolute Black oval rings (11-34/48/32) and recently my drivetrain began to get noisy too. Initially thought it was my bb or chain, but I traced it down to the clutch in the RX derailleur. I've had the AB rings for about a year now and while they don't shift as nice as the OE Ultegra rings, I do feel the benefit of the oval and the gearing really improve my riding to justify the slower shifting. If you decide to sell your set up, let me know.