I use NavLink to bold active link, but some of my link contain space and don't get bold when clicked, how to fix ?

categories.map((c,i) => (
        <NavLink
          key={i}
          exact
          activeClassName="is-active"
          to={`/series/category/${c}`}
        >
          {c}
        </NavLink>
    ))

I know for sure that it is due to the spaces because when I do this, links bold correctly (but the redirection doesn't work as my pages must contain space) :

to={`/series/category/${c.replace(/\s/g, "")}`}

Red squared links won't get bold.