South Korea has unique administrative unit, Dong(동) and Li(리). Li is similar to Dong. So I explain about Dong only.
There are two type of Dong, Administrative Dong(행정동) and Legal-status Dong(법정동).
Administrative Dong is used as administrative service area of Local Autonomous Entity. And Legal-status Dong is used for address system and trading land. Boundary of these two type of dong is differ each other. (more information : https://en.wikipedia.org/wiki/Dong_(administrative_division))
Problem is that these two of dong is SAME ADMINISTRATIVE LEVEL. So boundary of Dong is conflicted.
How can I solve this problem? OSM community in South Korea couldn’t get conclusion.
Don’t use boundary=administrative for both: reserve that for the actual administrative entity. For the other one use a different boundary=* tag. We have the same issue in the UK (although I think using admin_level=6 for one of those was not the best policy).
An alternative is to add a designation tag to delineate which type of legal entity it is (again we have this in the UK because we have a myriad of confusing administrative entities with different names in different part of the UK).
@muralito: this is a widespread & common problem where postal towns & cities do not accord with administrative ones. It certainly exists in the US and UK as well.