Flew back from SEA three days ago. Did online check-in and entered my KTN in the box provided (I have a UK passport with Global Entry)

Went to the desk to check-in and asked if she had my number for TSE-PRE and she confirmed it was all there and BP duly printed (with TSE-PRE on the BP too)

Went down the TSE-PRE line and the TSA agent was smiling with glee and about to tell me off seeing a UK passport with an Emirates BP. Just ignored her as she first told me I was in the wrong queue and then said ...never mind (as she looked at my BP)..... I just hate it when they suppose you have no clue

-Bottom line, enter your KTN during online checkin and all works just fine for TSE-PRE