Answer: In an established planting there is always reason for concern when die back of any kind occurs. Junipers are occasionally subject to a number of problems ranging from root rot to disease to insect infestation. Unfortunately, based on your description it is impossible to make a diagnosis. You might want to contact your County Extension for a more specific identification of the problem and recommended controls.
You can always prune out truly dead branches, but in this case the pattern may be a clue for daignosing the problem so you might wait until you have done with some certainty before you cut.
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