Formatting author names for citations

My EndNote has suddenly started formatting one particular author’s name incorrectly.  This is actual authors provided here.  The author is David L. Cooperrider.  My formatting entered in the author field in Endnote for several articles of  which he is the only or the first author is:

Cooperrider, David L.
Whitney, Diana
Stavros, Jacqueline M.

The citation, however, shows as (David L. Cooperrider, Whitney, & Stavros, 2008).   The formatting in the reference list is correct:    Cooperrider, D. L., Whitney, D., & Stavros, J. M. (2008).

I have checked all my references in EndNote several times, and this author is always listed as Cooperrider, David L. in the author field, regardless of whether he the only author, the first, or not the  first.   So it’s not an issue with two different formats in my EndNote for the same author.  There is no other author named Cooperrider in my EndNote references.

What is causing this and how can I fix it.  It’s driving me gently nuts!