diff --git a/lib/types/workload.go b/lib/types/workload.go
index dfd6e9d..6171a1e 100644
--- a/lib/types/workload.go
+++ b/lib/types/workload.go
@@ -52,7 +52,7 @@ type AWSWorkloadConfig struct {
 	ExternalID                              *uuid.UUID                          `json:"external_id" yaml:"external_id"`
 	ExtraClusterOidcUrls                    []string                            `json:"extra_cluster_oidc_urls" yaml:"extra_cluster_oidc_urls"`
 	ExtraPostgresDbs                        []string                            `json:"extra_postgres_dbs" yaml:"extra_postgres_dbs"`
-	FsxOpenzfsDailyAutomaticBackupStartTime string                              `json:"fsx_openzfs_daily_automatic_backup_start_time" yaml:"fsx_openzfs_daily_automatic_backup_start_time"`
+	FsxOpenzfsDailyAutomaticBackupStartTime *string                             `json:"fsx_openzfs_daily_automatic_backup_start_time" yaml:"fsx_openzfs_daily_automatic_backup_start_time"`
 	FsxOpenzfsMultiAz                       bool                                `json:"fsx_openzfs_multi_az" yaml:"fsx_openzfs_multi_az"`
 	FsxOpenzfsOverrideDeploymentType        *string                             `json:"fsx_openzfs_override_deployment_type" yaml:"fsx_openzfs_override_deployment_type"`
 	FsxOpenzfsStorageCapacity               int                                 `json:"fsx_openzfs_storage_capacity" yaml:"fsx_openzfs_storage_capacity"`
diff --git a/python-pulumi/src/ptd/pulumi_resources/aws_fsx_openzfs_multi.py b/python-pulumi/src/ptd/pulumi_resources/aws_fsx_openzfs_multi.py
index cace791..a202e45 100644
--- a/python-pulumi/src/ptd/pulumi_resources/aws_fsx_openzfs_multi.py
+++ b/python-pulumi/src/ptd/pulumi_resources/aws_fsx_openzfs_multi.py
@@ -11,7 +11,7 @@ class AWSFsxOpenZfsMultiArgs:
     automatic_backup_retention_days: pulumi.Input[int]
     copy_tags_to_backups: pulumi.Input[bool]
     copy_tags_to_volumes: pulumi.Input[bool]
-    daily_automatic_backup_start_time: pulumi.Input[str]
+    daily_automatic_backup_start_time: pulumi.Input[str] | None
     deployment_type: pulumi.Input[str]
     root_volume_configuration: AWSFsxOpenZfsMultiRootVolumeConfigurationArgs
     route_table_ids: list[str] | list[pulumi.Output[str]]
@@ -85,6 +85,15 @@ def __init__(
             # Use the first subnet as preferred for MULTI_AZ
             preferred_subnet_id = props.subnet_ids[0]
 
+        # Only pass daily_automatic_backup_start_time if it has a valid value.
+        # AWS doesn't return this field properly on refresh, causing state corruption
+        # with empty strings that fail validation. By making it conditional, we avoid
+        # the validation error and let AWS use its default if the state is corrupted.
+        daily_backup_time = props.daily_automatic_backup_start_time
+        if daily_backup_time is not None and len(daily_backup_time) != 5:
+            # Invalid value (likely empty string from corrupted state), don't pass it
+            daily_backup_time = None
+
         self.file_system = aws.fsx.OpenZfsFileSystem(
             f"{name}-filesystem",
             automatic_backup_retention_days=props.automatic_backup_retention_days,
@@ -97,7 +106,7 @@ def __init__(
             throughput_capacity=props.throughput_capacity,
             copy_tags_to_backups=props.copy_tags_to_backups,
             copy_tags_to_volumes=props.copy_tags_to_volumes,
-            daily_automatic_backup_start_time=props.daily_automatic_backup_start_time,
+            daily_automatic_backup_start_time=daily_backup_time,
             route_table_ids=props.route_table_ids,
             root_volume_configuration=root_volume_configuration,
             tags=props.tags,
diff --git a/python-pulumi/src/ptd/pulumi_resources/aws_workload_persistent.py b/python-pulumi/src/ptd/pulumi_resources/aws_workload_persistent.py
index e46635c..16128f2 100644
--- a/python-pulumi/src/ptd/pulumi_resources/aws_workload_persistent.py
+++ b/python-pulumi/src/ptd/pulumi_resources/aws_workload_persistent.py
@@ -866,10 +866,16 @@ def _define_fsx_openzfs(self) -> None:
             )
 
         else:
+            # Sanitize daily_automatic_backup_start_time - AWS doesn't return this field
+            # properly on refresh, causing state corruption with empty strings.
+            daily_backup_time = self.workload.cfg.fsx_openzfs_daily_automatic_backup_start_time
+            if daily_backup_time is not None and len(daily_backup_time) != 5:
+                daily_backup_time = None
+
             self.fsx_openzfs_fs = aws.fsx.OpenZfsFileSystem(
                 self.workload.compound_name,
                 automatic_backup_retention_days=30,
-                daily_automatic_backup_start_time=self.workload.cfg.fsx_openzfs_daily_automatic_backup_start_time,
+                daily_automatic_backup_start_time=daily_backup_time,
                 preferred_subnet_id=(subnet_ids[0] if deployment_type.startswith("MULTI") else None),
                 subnet_ids=subnet_ids,
                 deployment_type=deployment_type,