Im noticing the same on American save, if you check their personal details it will say they are Asian American but the volume you get is probably unrealistic for the 1920s. Not sure if thats fixable with how the game is designed though
One similar issue that is fixable is the names of generated workers not being made region specific. I have an asian-canadian worker named Ashton Ortiz, which should be a surname limited to hispanic/european wrestlers and a hispanic-American wrestler named Imran, which should probably be region locked to middle eastern workers. Also I have a 1920s Asian-American named Harvey Barry lol
Its not game-breaking, Im just having to give workers alter-ego names and assign a more accurate picture whenever I sign someone. Apart from that the actual meat and bones of the mod seem pretty good so far