Six-year-old SmartSolar MPPT 100/20 misreading battery voltage

A wind generator should have its own controller, that won’t be anything to do with the solar controller.
Would suggest checking all your wiring and connections between the solar controller and the battery, making sure that the wiring is the correct type, appropriate gauge for the current and round-trip distance, and the fuse or breaker between the controller and battery, as a simple loose connection or degraded/offbrand fuse or breaker could be causing what you’re seeing.