diff --git a/tools/tools/git/git-arc.sh b/tools/tools/git/git-arc.sh
--- a/tools/tools/git/git-arc.sh
+++ b/tools/tools/git/git-arc.sh
@@ -582,17 +582,10 @@
     echo '{"revisionIDs": [ '"${diff#D}"' ]}' | \
         arc_call_conduit -- differential.querydiffs |
         jq -r '.response | flatten | .[]' > "$diff_data"
-    author_addr=$(jq -r ".authorEmail?" "$diff_data" | sort -u)
-    author_name=$(jq -r ".authorName?" "$diff_data" | sort -u)
-
-    # JSON will return "null" when a field is not populated.
-    # Turn this string into an empty one.
-    if [ "$author_addr" = "null" ]; then
-        author_addr=""
-    fi
-    if [ "$author_name" = "null" ]; then
-        author_name=""
-    fi
+    # If the differential revision has multiple revisions, just take the first
+    # non-null value we get.
+    author_addr=$(jq -r ".authorEmail?" "$diff_data" | grep -v '^null$' | head -n 1)
+    author_name=$(jq -r ".authorName?" "$diff_data" | grep -v '^null$' | head -n 1)
 
     author=$(find_author "$user_addr" "$user_name" "$author_addr" "$author_name")