That's not something I can really fix. That's the data MDOT has in their linear reference model. I think it might be kinda considered a MS 43 Alternate, but it's not maintained by the state and instead locally maintained by the county... thus the weird designation.
I fixed a similar issue up in north Mississippi.

MDOT built a bypass of MS 25 around Amory. The old routing of MS 25 was still there, and the new routing someone had labeled "MS 25 Bypass". It turns out that MDOT turned the old route over to local governments and made the bypass the new route.
Local governments, to reduce confusion, decided to name the old routing of MS 25 as "Highway 125". They couldn't name it "Old Highway 25" because there's already an Old Highway 25... and having roads with the same name like that leads to confusion when someone inevitably has to call 911.