Data Point:
I purchased tickets in January for a trip to St Lucia in December for Xmas - trip was paid via AMEX Platinum and I paid for seat selection utilizing my airline credits...total was $250 but got reimbursed the $200
Earlier this month, I called and cancelled my flight due to COVID and got a flight credit for initial purpose, but was told I had get refunded the seat selection...I was refunded the full $250 on Sunday to my AMEX but no clawback