A while ago I tried to change trains from Elizabeth line to Central line at Ealing Broadway, however I could only see yellow readers showing entry / exit on the platform.
My understanding is that the platform validators were changed from yellow to pink shortly before the Elizabeth line opened west of Paddington into the core. I believe that they were on the London bound EL platform near to the access to the Underground platforms. The fare finder still mentions them if you ask for a fare like Hayes and Harlington to Queens Park. I haven’t been there for a while though.
That might explain it. So you arrived on the fast line up platform and went straight to the Underground? Have you managed to get a refund if you were overcharged for the day? Stating that the pink readers were inaccessible ought to be enough to get them to recalculate the journey.