diff --git a/xuqm-bugcollect-service/src/main/resources/db/migration/V4__bugcollect_v12.sql b/xuqm-bugcollect-service/src/main/resources/db/migration/V4__bugcollect_v12.sql
index 0dc080a..10c33bb 100644
--- a/xuqm-bugcollect-service/src/main/resources/db/migration/V4__bugcollect_v12.sql
+++ b/xuqm-bugcollect-service/src/main/resources/db/migration/V4__bugcollect_v12.sql
@@ -11,8 +11,11 @@ CREATE TABLE IF NOT EXISTS log_issue_users (
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
 -- HMAC signing secret for webhooks (nullable = no signing)
+-- MySQL does not support ADD COLUMN IF NOT EXISTS.
+-- If the column already exists (e.g. partial re-run), this migration will fail.
+-- V5__bugcollect_v12_repair.sql handles the repair case.
 ALTER TABLE log_webhooks
-    ADD COLUMN IF NOT EXISTS secret VARCHAR(64) NULL COMMENT 'HMAC-SHA256 signing secret; NULL = no signature';
+    ADD COLUMN secret VARCHAR(64) NULL COMMENT 'HMAC-SHA256 signing secret; NULL = no signature';
 
 -- Session tracking table (ingestion path via /sessions/batch is not yet implemented)
 CREATE TABLE IF NOT EXISTS log_sessions (
@@ -21,7 +24,7 @@ CREATE TABLE IF NOT EXISTS log_sessions (
     session_id   VARCHAR(64)  NOT NULL,
     user_id      VARCHAR(128) NULL,
     platform     VARCHAR(16)  NULL,
-    release      VARCHAR(32)  NULL,
+    `release`    VARCHAR(32)  NULL,
     environment  VARCHAR(32)  NULL,
     sdk_name     VARCHAR(64)  NULL,
     sdk_version  VARCHAR(32)  NULL,
@@ -35,5 +38,4 @@ CREATE TABLE IF NOT EXISTS log_sessions (
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
 
 -- Ensure event_id has an index (was added as NULL in V3)
--- Note: MySQL does not support ALTER TABLE ADD INDEX IF NOT EXISTS
 CREATE INDEX idx_lie_event_id ON log_issue_events (event_id);