I noticed my other reservation had the same issue as I had to rebook it. Christina has been responsive and managed to get a response from the first hotel who now refunded me. Is the fx credit card spread (2.5% each way converting back and forth = 5%) something worth pursuing? It will be around CAD $25 combined for my two stays and it would not have been incurred if Marriott did not charge me.

Both mine are Marriott branded properties.