To be brief: changes occurred last year when China visa officers began to strictly determine whether visa applicants with a Chinese background were in fact still Chinese citizens and ineligible to travel to China on a foreign passport. More a change of enforcement policy than a change of actual citizenship rules.
And the historical residency doc check on parents of ethnic Chinese minors born in Western jus soli countries (maybe even PR-jus-soli ones) is a post-COVID thing. It wasn't heard of when Chinese HK/Mers naturalized in the West were first denied their first visa.