diff --git a/inc/field.class.php b/inc/field.class.php
index 6ff05e1d..039e812f 100644
--- a/inc/field.class.php
+++ b/inc/field.class.php
@@ -1011,7 +1011,7 @@ function(obj, item) {
                         var multiple_matches = item.name.match(/^(.+)\[\]$/);
                         if (multiple_matches) {
                             var name = multiple_matches[1];
-                            if (!(name in obj)) {
+                            if (!(name in obj) || obj[name] == "") {
                                 obj[name] = [];
                             }
                             obj[name].push(item.value);