In this paper, we review the underappreciated theorem by Lotz that tells us that every strongly continuous operator semigroup on a Grothendieck space with the Dunford-Pettis property is automatically uniformly continuous. A large class of spaces that carry these geometric properties are ${\mathrm{L}}^{\mathrm{\infty }}(\mathrm{\Omega },\mathrm{\Sigma },\mu )$ for non-negative measure spaces. This shows once again that ${\mathrm{L}}^{\mathrm{\infty }}$-spaces have to be treated differently.