I suspect they are prioritizing the other gas station brands because they paid for preference, and selected "Maverik" as one of their keywords, but the impact to me is that the exact thing I searched for doesn't come up even though I know it's there because I've stopped there before.
If somebody gives me a simple maps product algorithm that just shows me what I'm asking for without preferencing paid people using key words and I'll likely switch. I've loved Google for many years but they are getting much worse.