Yes, we agree these plants are Privet (Ligustrum, probably Ligustrum japonicum) and not Euonymus. Our plant pathologist took a look at the photos and does not recognize the leaf symptoms as belonging to a pest or disease issue known to damage privet. Instead, this appears to be environmental damage, which would mean they're a result of weather conditions or root health decline (such as from soil that got too dry or too wet at some point) contributing to the leaf lesions and shedding. Some of the leaf damage might be winterburn, which happens to many evergreens (especially those, like evergreen privets, which are closer to the limits of their cold tolerance in Maryland) during periods of freezing temperatures when dry winds or other conditions don't allow the plants to replace moisture being lost from their leaves. Leaf loss can be a more extreme manifestation of winterburn, but it can occur. Root dieback is another possibility as it too can cause leaf shedding. There is no treatment for winterburn after it occurs; the plant will simply have to replace lost foliage as it is able over the next one or several growing seasons. Preventing it going forward isn't always possible either, but monitoring the root zone for watering needs during mild winter weather can help minimize winterburn risk.

Since privet is invasive in Maryland, we suggest replacing the shrubs if you are able. (It can be done in stages if needed.) While other commonly-grown evergreen shrubs like Japanese Euonymus, Aucuba, Cherrylaurel, and several species of holly are similarly not native, few of them have proven invasive thus far. (There are a few native evergreen holly shrubs, though not many which would reach the size you prefer while retaining a dense complement of leaves.) If you are interested in using an alternative evergreen in these areas, we can suggest some candidates once we have more information about the site conditions and what restrictions you may have on mature size (without pruning) for the space available, and whether plantings need to be unpalatable to deer.

Miri