diff --git a/js/libtextsecure.js b/js/libtextsecure.js
index bf44b341..a079605f 100644
--- a/js/libtextsecure.js
+++ b/js/libtextsecure.js
@@ -38249,7 +38249,7 @@ axolotlInternal.RecipientRecord = function() {
                 if (group === undefined)
                     throw new Error("Tried to update numbers for unknown group");
 
-                if (numbers.filter(function(number) { return !textsecure.utils.isNumberSane(number); }).length > 0)
+                if (numbers.filter(textsecure.utils.isNumberSane).length < numbers.length)
                     throw new Error("Invalid number in new group members");
 
                 if (group.numbers.filter(function(number) { return numbers.indexOf(number) < 0 }).length > 0)
diff --git a/libtextsecure/storage/groups.js b/libtextsecure/storage/groups.js
index 959966a9..50c70ede 100644
--- a/libtextsecure/storage/groups.js
+++ b/libtextsecure/storage/groups.js
@@ -136,7 +136,7 @@
                 if (group === undefined)
                     throw new Error("Tried to update numbers for unknown group");
 
-                if (numbers.filter(function(number) { return !textsecure.utils.isNumberSane(number); }).length > 0)
+                if (numbers.filter(textsecure.utils.isNumberSane).length < numbers.length)
                     throw new Error("Invalid number in new group members");
 
                 if (group.numbers.filter(function(number) { return numbers.indexOf(number) < 0 }).length > 0)