Complex sentence: This spelling could mislead people to think that Gladbach was a borough of Munich ("München" in German), and consequently the name was changed to Mönchen Gladbach in 1950 and Mönchengladbach in 1960.
Split into simpler sentences: This spelling could lead to the fallacy, that Gladbach is a borough of Munich ("München" in German). So the name was changed to Mönchen Gladbach in 1950 resp. Mönchengladbach in 1960.