I'm a EU national with UK settled status, flying from Munich to London Heathrow with Lufthansa. At the airport, Germany's own border control took no issues with me, checked my passport and waved me through. However, Lufthansa seemed to have dedicated UK passport control that their employees man where I had to present my passport for inspection. The person in charge flipped through it and asked if the passport was new. I was rather surprised by the question but I said it was issued in 2020 (which would have been made clear on the front page). She seemed to find it strange that it had not been "used", as there were no entry/exit stamps anywhere (plus, I keep it in a passport holder and generally try to take good care of it, possibly giving the impression it's brand new). I said when I go to the UK I always go through the electronic gates. However, she was still not satisfied (not sure if my middle Eastern name/looks played a role, but I'm always wary of extra checks on account of that), so asked me for any other documents proving I'm a national of said EU state. I said I don't have them on me but that I do have my UK driving licence on me which she can check. She inspected it and seemed to be finally satisfied that everything is in order and let me proceed.
I've done this route in the past and there were no such checks, this was the first time, so not sure what's changed. I also wonder what it is I could have done differently to avoid the extra hassle and what about me gave her pause. I was lucky I had my driving licence on but dread to think I could have been potentially denied boarding with little recourse. I have lived and worked in the UK for many years, so do worry sometimes about my ability to re-enter the country, I live and work there and own my home there, so it's a scary prospect for me. I suspect other EU nationals might be subject to the same sort of unfair scrutiny where their right to enter the UK is decided by a non-UK border official.