Suno reusing instrumentals from already generated songs...

I've known Suno to repeat lyrics in a song, but I've discovered now that it can also repeat instrumental arrangements. I even got a literal copy of the same song I've already generated musically, but with the new lyrics I wrote.

I'm using Persona and I'd say I've gotten the exact same instrumental, at least the first 30 seconds of the song, three times out of 20.

Is this because of the Persona? Is it because the prompt/genre is too niche for Suno to create variety?

Thoughts?