I understand the Marriot Chateau was renovated but wasn't aware of a renovation at the Le Meriden. Judging by the pictures it appears to be a bath renovation only. The bathrooms were indeed overdue for one. Pre-renovation I had no issues being upgraded to a Junior Suite.
It's very possible the rooms were already pre-blocked for another elite but kept in inventory in case of a last minute booking. During SPG days, I've seen a suite as an upgrade assigned in the morning during a stay at Le Meridien Wien but when I arrived at the check-in, it had changed to a regular room..