Hey @Kostya,
Have you tried this:
Resolution to Repeating Values
More info here: API Result Display on Repeat - #12 by joeyology
In your Collections drag the field you’re displaying to the top of the fields in the External Collection (there is a screenshot in my initial post). In my case I was using “Name”. Now see above: “Name is unique but it wasn’t at the top by default so you need to drag it to the top manually. This could be an ID or similar in your case”
This fixed it for me. I hope that helps