I received the email about hotels charging the deposit after July 17, but I haven’t been charged yet. The reservation is confirmed in the housing portal, but I’m just afraid that there may be a glitch or something. It’s for the Sheraton City Centre in case anyone is at the same hotel. Should I be concerned?

Very common. No, you shouldn't be concerned. It couldn't hurt to validate the reservation though. You can do that via their app (if you used your loyalty number) or by calling them.