diff --git a/third_party/terraform/resources/resource_compute_instance_group_manager.go b/third_party/terraform/resources/resource_compute_instance_group_manager.go
index 061fd62c0e75..70bbdc4afa43 100644
--- a/third_party/terraform/resources/resource_compute_instance_group_manager.go
+++ b/third_party/terraform/resources/resource_compute_instance_group_manager.go
@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/hashicorp/terraform-plugin-sdk/helper/customdiff"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/validation"
@@ -93,7 +94,6 @@ func resourceComputeInstanceGroupManager() *schema.Resource {
 				Optional:         true,
 				Computed:         true,
 				Removed:          "This field has been replaced by `version.instance_template`",
-				ConflictsWith:    []string{"version"},
 				DiffSuppressFunc: compareSelfLinkRelativePaths,
 			},
 
diff --git a/third_party/terraform/resources/resource_compute_region_instance_group_manager.go b/third_party/terraform/resources/resource_compute_region_instance_group_manager.go
index 02ea23f90691..c7f6d3f119cd 100644
--- a/third_party/terraform/resources/resource_compute_region_instance_group_manager.go
+++ b/third_party/terraform/resources/resource_compute_region_instance_group_manager.go
@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/hashicorp/terraform-plugin-sdk/helper/customdiff"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/hashcode"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/resource"
 	"github.com/hashicorp/terraform-plugin-sdk/helper/schema"
@@ -89,8 +90,9 @@ func resourceComputeRegionInstanceGroupManager() *schema.Resource {
 			},
 
 			"instance_template": {
-				Type:    schema.TypeString,
-				Removed: "This field has been replaced by `version.instance_template` in 3.0.0",
+				Type:     schema.TypeString,
+				Optional: true,
+				Removed:  "This field has been replaced by `version.instance_template` in 3.0.0",
 			},
 
 			"version": {