That looks more like just typical winter discoloration. Blighted shrubs will show obviously dead, dry portions, which I am not seeing in your photo.

Geographic location of planting?

New Jersey. Zone 6b. It was planted straight into clay soil and probably never fertilized. It’s watered by sprinklers. Has been turning yellower with time even in summer, but the back of the shrubs (on the shady side) used to be green.

First paragraph under Boxwood Culture might pertain.

https://extension.psu.edu/boxwoods-for-pennsylvania-landscapes

Thank you.