Yuck...I don't think you are off-base at all. Did you take a photo of the offending glass? @:-) A strategic email to SPG might yield good things, if so. :-: Double-disgusting since this is a hotel that is less than 1-year old...I hope that this is due to an untrained housekeeping staff...
...especially troubling due to the lack of Hyatt properties near MIA.