diff --git a/.changes/unreleased/Fixes-20250128-135509.yaml b/.changes/unreleased/Fixes-20250128-135509.yaml
new file mode 100644
index 00000000000..4ba96df354a
--- /dev/null
+++ b/.changes/unreleased/Fixes-20250128-135509.yaml
@@ -0,0 +1,6 @@
+kind: Fixes
+body: Loosen validation on freshness to accomodate previously wrong but harmless config.
+time: 2025-01-28T13:55:09.318833-08:00
+custom:
+  Author: ChenyuLInx peterallenwebb
+  Issue: "11123"
diff --git a/core/dbt/artifacts/resources/v1/model.py b/core/dbt/artifacts/resources/v1/model.py
index aca176ad397..2a62665e4df 100644
--- a/core/dbt/artifacts/resources/v1/model.py
+++ b/core/dbt/artifacts/resources/v1/model.py
@@ -8,12 +8,11 @@
     CompiledResource,
     DeferRelation,
     NodeVersion,
-    Time,
 )
 from dbt.artifacts.resources.v1.config import NodeConfig
 from dbt_common.contracts.config.base import MergeBehavior
 from dbt_common.contracts.constraints import ModelLevelConstraint
-from dbt_common.dataclass_schema import dbtClassMixin
+from dbt_common.dataclass_schema import ExtensibleDbtClassMixin, dbtClassMixin
 
 
 @dataclass
@@ -42,14 +41,14 @@ class ModelFreshnessDependsOnOptions(enum.Enum):
 
 
 @dataclass
-class ModelBuildAfter(Time):
+class ModelBuildAfter(ExtensibleDbtClassMixin):
     depends_on: ModelFreshnessDependsOnOptions = ModelFreshnessDependsOnOptions.any
     count: int = 0
     period: TimePeriod = TimePeriod.hour
 
 
 @dataclass
-class ModelFreshness(dbtClassMixin):
+class ModelFreshness(ExtensibleDbtClassMixin):
     build_after: ModelBuildAfter = field(default_factory=ModelBuildAfter)
 
 
diff --git a/schemas/dbt/manifest/v12.json b/schemas/dbt/manifest/v12.json
index af7f5b2bd65..0be0a978588 100644
--- a/schemas/dbt/manifest/v12.json
+++ b/schemas/dbt/manifest/v12.json
@@ -4848,6 +4848,13 @@
                         "type": "object",
                         "title": "ModelBuildAfter",
                         "properties": {
+                          "depends_on": {
+                            "enum": [
+                              "all",
+                              "any"
+                            ],
+                            "default": "any"
+                          },
                           "count": {
                             "type": "integer",
                             "default": 0
@@ -4859,19 +4866,12 @@
                               "day"
                             ],
                             "default": "hour"
-                          },
-                          "depends_on": {
-                            "enum": [
-                              "all",
-                              "any"
-                            ],
-                            "default": "any"
                           }
                         },
-                        "additionalProperties": false
+                        "additionalProperties": true
                       }
                     },
-                    "additionalProperties": false
+                    "additionalProperties": true
                   },
                   {
                     "type": "null"
@@ -14817,6 +14817,13 @@
                               "type": "object",
                               "title": "ModelBuildAfter",
                               "properties": {
+                                "depends_on": {
+                                  "enum": [
+                                    "all",
+                                    "any"
+                                  ],
+                                  "default": "any"
+                                },
                                 "count": {
                                   "type": "integer",
                                   "default": 0
@@ -14828,19 +14835,12 @@
                                     "day"
                                   ],
                                   "default": "hour"
-                                },
-                                "depends_on": {
-                                  "enum": [
-                                    "all",
-                                    "any"
-                                  ],
-                                  "default": "any"
                                 }
                               },
-                              "additionalProperties": false
+                              "additionalProperties": true
                             }
                           },
-                          "additionalProperties": false
+                          "additionalProperties": true
                         },
                         {
                           "type": "null"