Terraform does this when the real infrastructure doesn’t match the configuration exactly, even if the difference seems harmless.

Small drifts—like default values set by the provider, manual console changes, or computed fields—can cause Terraform to think a resource needs replacement. This often happens after importing existing resources or tweaking things manually outside Terraform.

The plan output usually tells you which attribute is triggering the change, but it’s easy to overlook.

Takeaway: Terraform is strict by design; even small mismatches can cause replacement.