She looks fine to me. Definitely no deficiency or burn for that matter. Looks more like either old damage to the leaf, or there was a bug in there nibbling. When leave get damaged (torn, poked, or a tiny bit eaten) the damage may look more pronounced as the leaf grows and becomes bigger. As the leaf grows, so does the appearance of the otherwise tiny damaged surface. Also keep in mind that leaf damage never really goes away. A burnt or damaged leaf will be damaged forever. If the new growth is healthy lookin then you're good.
Honestly though she looks healthy.