One Application load balancer is integrated with WAF web acl . And these webacl rule is managed by firewall manager from organisation account . Suddenly in the integration tab of ALB started showing that alb is no associated with WAF . Have any one faced these type of issue .
Checked in the cloudtrail logs and found that these are be removed by firewall manager .
Found the solution . Actually firewall manager is controlling the waf integration . The rule is like if associated accounts's loadbalancer have specific tag then integrate the alb with waf else not . So in my cases tags of the load balancer was wrong .