Nether portals have a feature where if you construct one in the overworld and its linked coordinates in the nether are outside the nether border, the portal is generated right inside the nearest point on the border wall.

This feature is not functioning in negative coordinate values. Only positive coordinate values properly switch to match the border of the target world. This means that the only functioning quadrant is (positive,positive). All other quadrants have at least one negative value and thus generate your portal outside the border which results in immediate death.