This doesn’t look like boxwood blight as shown in photos in this OSU article. Look carefully at the plants where they go from green to brown. Are you seeing any spotted foliage? What about the stems in those places, do you see canker or discoloration or sunken areas? Share photos of what you find.
This is a quote from that OSU page: “Boxwood plants are susceptible to a number of other diseases, some of which can look like boxwood blight. Volutella blight, Macrophoma leaf spot, and boxwood decline can all be confused with boxwood blight. Winter injury and sunscald can also look like the disease.”
This article from Ohio has great photos about canker and cold damage.
A prior Ask Extension Q&A here discusses root rot, crown blight, and even boxwood decline in the follow up sections. There is a photo of stem damage from rot in the PNW Handbook page. Share a photo if you find similar on your plants.
Yours look just like my neighbor’s plants the last few years. He pruned one back severely as a rejuvenation, and so far it’s growing back green, so our theory is cold damage from the snow and ice buildup in recent years. He plans to sweep them off in the future when we get snow or a silver thaw. Did yours have snow & ice build up?
The vertical browning along one side where the plants were shorn doesn’t look like possible ice build up though. Was that healthy before being trimmed? How long has it been like that without regrowth?
So, what is the next step for you? In addition to a close examination of the shrub, and sharing photos of what you find, tell us how you water and otherwise care for the plants. How long have the plants been showing this damage? Any changes in their sun exposure or root zone? (Maybe a tree was removed or a ditch dug next to the hedge.)
If this is a high-value plant in your landscape, consider hiring a certified arborist to make a site visit. I hope we can answer your questions remotely on this forum though.