I've seen some non-definitive discussions of this on some forums, so I thought I'd share in case someone else has the issue.
2017 Escape Titanium AWD 2.0-L
I'm just under 10,000 miles on it, though this started happening a few thousand miles ago.
When backing up, especially backing up and turning as if you are coming out of a parking space in store parking lot, or backing out of a driveway, After moving a few yards I'd get a solid "CLUNK" both sound and feel that appeared to be coming form the rear end (of the Escape, not me). It was solid enough that my instinct was to cover the brake like I'd hit something. The best I can describe it would be as if I'd run over a partially full beer can with one of the back wheels. The problem grew more and more consistent.
I'd asked about it at the dealer briefly and they just stared at me so I've been ignoring it, until it was time for the oil change and checkup. I mentioned it on the work order and the tech definitely noticed it when he went to get the car (good luck for me).
They looked at a lot of the undercarriage and couldn't find a problem, but didn't want me to drive it until they found it, so they gave me a ride home.
Long story short, they've replaced the "Four Wheel Drive Control Module" located in one of the back kick-panels and believe they have solved the problem. That's ONE of the theories I've seen people talking about, so maybe this will help someone else get to the solution more quickly.