Can't tell about North Korean, but "-는 데서" is commonly used in South Korea. You might have missed it because in South Korea it is written with a space: 데 is a noun (의존 명사) meaning "place" or "thing(?)". 서 is just short for "-에서".
And you are right, they are completely different from verb suffix "-는데".
Here are some random sentences I found around the web. Here, 데서 can be replaced by 것에서 without change of meaning:
공연은 [무대 위에 광주의 축소판을 구현하는 데]서 시작한다.
= The performance begins with setting up a miniature Gwangju on the stage.
[현재를 부정하는 데]서 오는 폭발적인 상상력, SF의 매력이죠
= The charm of SF is explosive imagination coming from denying the present.
이 방식은 [하나의 케이블에 복수의 호스트를 연결하는 데]서 발생하는 많은 문제를 해소하였습니다.
This method solved many problems that arose from connecting multiple hosts with a single cable.
A more informal example using "-는 데" (where you can't use 것):
내일 운동하는 데로 나와. = Come to the place where [we] work out, tomorrow.
점심은 맨날 먹는 데서 먹자. = Let's eat lunch where we eat it every day (i.e., at the usual place).