This does not look like a disease or insect issue.  This looks like winter color on the boxwood.  Stressors such as cold dry weather and a lack of moisture can cause some dessication.  It is located against brick in a sunny area and this can be a factor. Sometimes this injury can be scattered. Maintain adequate soil moisture in the fall to prevent winter desiccation.
 At this point we do not recommend a control.  Monitor the shrub during the growing season and you may have to do some pruning eventually.
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