Right clicking on google maps and selecting the lat long to put is something I do many times when investigating a sighting however I was looking into geolocating a sighting in South Korea when i went to grab lat and long it didn't work.

It seems there is a polygon drawn over South Korea that disables it, as it also doesn't work for the regions of North Korea that are south of South Korea most northern point, but does work for Japanese islands that are north of South Koreas southern points.

It seems this is a security measure

Source: https://www.reddit.com/r/explainlikeimfive/comments/14zb9ks/eli5_why_cant_google_maps_generate_its_own/

South Korea

China

Japan