As already pointed out in the old Developer Forum CodeDeploy B/G deploy is failing if the AutoScalingGroup has some AutoScalingPolicy attached because it looses the attachment to the original TargetGroup.
Has anybody found a better solution than manually re-attaching it?
Attaching the policies instead of the target is also a possibility, but it makes the management of the policies not in CloudFormation. BTW, the old workaround only worked with "classic LB", it can't be implemented with current ALBs.
It is "funny" that AWS is aware of this severe bug but did not fixed it yet, after 5 years ;(