It’s weird, I’ve seen quite a few posts like the OP relatively recently complaining about how Spotify premium suddenly has ads now. Yet I’ve had a premium subscription for 10 year now (rip my $$$) and have yet to hear a single ad since subbing. Well, unless it’s a sponsored segment placed in there by the creator.
Maybe it’s because I don’t listen to many podcasts? But even when I have, I have literally never heard a Spotify ad. Maybe the specific podcasts I’ve listened to don’t have the “feature” that OP describes.
Maybe it’s regional? Maybe it’s an error? Maybe OP doesn’t recognize ads placed there by the content creator?