No, that's incorrect. Not one of the podcasts i listen to re-master their mp3s, the checksums stay the same. In fact, most of the podcasts i listen to have no ads at all. I wonder if there's some misunderstanding, here. If i go watch like an LTT video where they had a sponser, 5 years ago, that same "native ad" will be in the video. I'm specifically saying that the podcast apps i use do not inject ads, but podcasts themselves will do native advertising, i consider these completely different things.

https://podcastindex.org/apps podcasting 2.0 app index.