Three times this year on PEK_EWR (777-200ER) I reserved (months in advance) premium exit seat 32A (no issue as platinum elite). On each occasion I was reseated some 48 hours before flight-time to a less preferred seat (and on the continuing leg EWR-IAH to a middle row seat!). First time I did not notice till check-in, by then too late: next time I was ready and via CO elite supervisor got my seat back - OK. Last time, I was 'reseated' AGAIN 24 hours before flight-time (back again to the old bad seats), seat 32A was re-assigned and it was too late to do anything.
Here the Platinum Elite are actually ending up with worse seats than non-elites with the cheapest discount seat. By all means let CO sell premium seats, but non let them be assigned in the first place!!!!
No useful response yet from CO