Okay all you Woodworkers out there

I have a tech question

I’ve noticed that the 1/2” diameter zinc plated carriage bolts I’ve been using on my box are rusting rather quickly on the surface contacting the treated lumber

Perhaps I should have gotten the dull finish dipped galvanized bolts instead

Any input on this is appreciated; as I’ve removed some bolts to install longer or shorter ones & noticed the rust/corrosion on the shanks

Thanks