diff --git a/bin/tests/system/digdelv/tests.sh b/bin/tests/system/digdelv/tests.sh
index 65bf8f50f8..249c9989d4 100644
--- a/bin/tests/system/digdelv/tests.sh
+++ b/bin/tests/system/digdelv/tests.sh
@@ -645,6 +645,18 @@ if [ -x "$DIG" ]; then
   if [ $ret -ne 0 ]; then echo_i "failed"; fi
   status=$((status + ret))
 
+  if [ $HAS_PYYAML -ne 0 ]; then
+    n=$((n + 1))
+    ret=0
+    echo_i "check that dig processes +ednsopt=key-tag:<value-list> +yaml ($n)"
+    dig_with_opts @10.53.0.3 +yaml +ednsopt=key-tag:00010002 a.example +qr >dig.out.test$n 2>&1 || ret=1
+    $PYTHON yamlget.py dig.out.test$n 0 message query_message_data OPT_PSEUDOSECTION EDNS KEY-TAG >yamlget.out.test$n 2>&1 || ret=1
+    read -r value <yamlget.out.test$n
+    [ "$value" = "[1, 2]" ] || ret=1
+    if [ $ret -ne 0 ]; then echo_i "failed"; fi
+    status=$((status + ret))
+  fi
+
   n=$((n + 1))
   echo_i "check that dig processes +ednsopt=key-tag:<malformed-value-list> and FORMERR is returned ($n)"
   ret=0
diff --git a/lib/dns/message.c b/lib/dns/message.c
index 0f046f78be..8673dc7121 100644
--- a/lib/dns/message.c
+++ b/lib/dns/message.c
@@ -3809,7 +3809,7 @@ dns_message_pseudosectiontoyaml(dns_message_t *msg, dns_pseudosection_t section,
 				break;
 			case DNS_OPT_KEY_TAG:
 				if (optlen > 0U && (optlen % 2U) == 0U) {
-					const char *sep = "";
+					const char *sep = " [";
 					while (optlen > 0U) {
 						uint16_t id =
 							isc_buffer_getuint16(
@@ -3820,7 +3820,7 @@ dns_message_pseudosectiontoyaml(dns_message_t *msg, dns_pseudosection_t section,
 						sep = ",";
 						optlen -= 2;
 					}
-					ADD_STRING(target, "\n");
+					ADD_STRING(target, " ]\n");
 					continue;
 				}
 				break;