Just connected through there and no secondary on way out to EZE but yes on way back to ATL (as mentioned above, it's just certain regions). It's strange though as they use retractable bollards like grocery store line management but they have to put in security guards because people keep trying to go under them as it doesn't really look like a checkpoint. They didn't take water bottles at the gate but were very strict about not having liquids - lots of people drinking in line.

Not sure about bottles at main security checkpoint though.