To Clarify, Naming of trains on IRI doesn't go by books always. It sometimes goes by Popularity. As this train shares rake with Padmavati Express, the rake keeps its name and travels through this route. So the train users popularized the name as Padmavati Express as thats what they see on the train rake most of the times. Moreover the SCR staff itself sometimes call it Padmavati Express officially as well. There were occasions where they mentioned it as Padmavati Express in official press releases too. So we wouldn't need a specific official name change publication for it.
For Ex see this press release:
/news/post/240926