Intermittent “low battery voltage” warning

I recently purchased this vehicle about a month ago, I’m aware it has higher mileage for the year of the vehicle.

Since I’ve had this vehicle I’ve been getting intermittent warnings on the dash saying I have “low battery voltage” but the gauge says it’s charging to 15V.

First we tested the battery and I found out they sold me a car with a battery that had a health of 26% so I brought it back and they put in a new battery. A week later I was still having the same issue so they sent me to a shop where they have an account set up and the mechanic there said my battery is being overcharged and it’s likely the alternator. They changed the alternator the next day at the dealerships cost. Two days later I am still having the same issue with a new battery and alternator. This message typically comes on when I’m accelerating after being stopped at a light. It does not come on all time, I’ve already contacted the dealership and they are sending me to the same shop again tomorrow but I want another opinion. I’m thinking it could be a wiring issue? Either a corroded wire in the bulk head or battery? Maybe even the remote sense wire?

Any feedback would be greatly appreciated!

Thanks