diff --git a/CertificateManager/metadata/V1/CertificateManager.php b/CertificateManager/metadata/V1/CertificateManager.php
index b96ee3c4f020..cdf10e409c8a 100644
Binary files a/CertificateManager/metadata/V1/CertificateManager.php and b/CertificateManager/metadata/V1/CertificateManager.php differ
diff --git a/CertificateManager/src/V1/Certificate.php b/CertificateManager/src/V1/Certificate.php
index 36e00eaa2dec..9a0e5961ca84 100644
--- a/CertificateManager/src/V1/Certificate.php
+++ b/CertificateManager/src/V1/Certificate.php
@@ -48,7 +48,9 @@ class Certificate extends \Google\Protobuf\Internal\Message
     private $labels;
     /**
      * Output only. The list of Subject Alternative Names of dnsName type defined in the
-     * certificate (see RFC 5280 4.2.1.6)
+     * certificate (see RFC 5280 4.2.1.6).
+     * Managed certificates that haven't been provisioned yet have this field
+     * populated with a value of the managed.domains field.
      *
      * Generated from protobuf field <code>repeated string san_dnsnames = 6 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      */
@@ -96,7 +98,9 @@ class Certificate extends \Google\Protobuf\Internal\Message
      *           If set, contains configuration and state of a managed certificate.
      *     @type string[]|\Google\Protobuf\Internal\RepeatedField $san_dnsnames
      *           Output only. The list of Subject Alternative Names of dnsName type defined in the
-     *           certificate (see RFC 5280 4.2.1.6)
+     *           certificate (see RFC 5280 4.2.1.6).
+     *           Managed certificates that haven't been provisioned yet have this field
+     *           populated with a value of the managed.domains field.
      *     @type string $pem_certificate
      *           Output only. The PEM-encoded certificate chain.
      *     @type \Google\Protobuf\Timestamp $expire_time
@@ -326,7 +330,9 @@ public function setManaged($var)
 
     /**
      * Output only. The list of Subject Alternative Names of dnsName type defined in the
-     * certificate (see RFC 5280 4.2.1.6)
+     * certificate (see RFC 5280 4.2.1.6).
+     * Managed certificates that haven't been provisioned yet have this field
+     * populated with a value of the managed.domains field.
      *
      * Generated from protobuf field <code>repeated string san_dnsnames = 6 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      * @return \Google\Protobuf\Internal\RepeatedField
@@ -338,7 +344,9 @@ public function getSanDnsnames()
 
     /**
      * Output only. The list of Subject Alternative Names of dnsName type defined in the
-     * certificate (see RFC 5280 4.2.1.6)
+     * certificate (see RFC 5280 4.2.1.6).
+     * Managed certificates that haven't been provisioned yet have this field
+     * populated with a value of the managed.domains field.
      *
      * Generated from protobuf field <code>repeated string san_dnsnames = 6 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      * @param string[]|\Google\Protobuf\Internal\RepeatedField $var