11/17/17 LAX-HKG on CX883. I added my KTN at online check-in at T-48 hrs. Couldn’t get boarding pass until T-24 hrs (normal due to US Gov’t Regs). At T-24hrs, mobile boarding pass said TSA Pre-Check. Dropped off a bag at the TBIT check-in counter at T-3 hrs and agent printed new boarding passes that said TSA Pre-Check. I walked to the Terminal 4 Pre-Check line and both my printed boarding pass and my mobile boarding pass screenshot were rejected as “PRECHECK INVALID”. I was directed to the normal line at T4, and went through with no problem. They even they let me keep my shoes on due to the TSA Pre-Check on my boarding pass. ^