diff --git a/web/src/hooks/use-config-override.ts b/web/src/hooks/use-config-override.ts
index 689e99f4b1..90ce717293 100644
--- a/web/src/hooks/use-config-override.ts
+++ b/web/src/hooks/use-config-override.ts
@@ -59,6 +59,64 @@ function stripHiddenPaths(value: JsonValue, hiddenFields: string[]): JsonValue {
   return cloned;
 }
 
+/**
+ * Field paths that the backend resolves per-camera at runtime (from `fps`,
+ * stream introspection, or other camera-local state) but defaults to `None`
+ * in the global Pydantic model. Because the `/config` endpoint serializes
+ * with `exclude_none=True`, these paths are absent from the global section
+ * yet always populated on cameras, which would otherwise make every camera
+ * appear to override fields the user never set globally.
+ */
+const AUTO_DERIVED_FIELDS: Record<string, readonly string[]> = {
+  detect: [
+    "width",
+    "height",
+    "min_initialized",
+    "max_disappeared",
+    "stationary.interval",
+    "stationary.threshold",
+  ],
+};
+
+/**
+ * Drop auto-derived field paths from the camera value when the global value
+ * has no explicit setting for that path. If the user later sets one of these
+ * fields globally, the path will be present in `globalValue` and normal
+ * comparison resumes.
+ */
+function stripAutoDerivedMissingFromGlobal(
+  sectionPath: string,
+  globalValue: JsonValue,
+  cameraValue: JsonValue,
+): JsonValue {
+  const fields = AUTO_DERIVED_FIELDS[sectionPath];
+  if (!fields || !isJsonObject(cameraValue)) return cameraValue;
+  const cloned = cloneDeep(cameraValue) as JsonObject;
+  for (const path of fields) {
+    if (get(globalValue, path) === undefined) {
+      unsetWithWildcard(cloned as Record<string, unknown>, path);
+    }
+  }
+  return cloned;
+}
+
+/**
+ * Whether the given field is auto-derived for `sectionPath` and the global
+ * value at that path is missing — in which case a per-camera value should
+ * not be treated as an override.
+ */
+function isAutoDerivedMissingFromGlobal(
+  sectionPath: string,
+  fieldPath: string,
+  globalValue: unknown,
+): boolean {
+  const fields = AUTO_DERIVED_FIELDS[sectionPath];
+  if (!fields) return false;
+  if (!fields.includes(fieldPath)) return false;
+  const value = get(globalValue as JsonObject, fieldPath);
+  return value === undefined || value === null;
+}
+
 /**
  * Collapse null and empty-object values for override comparisons so
  * semantically equivalent shapes match. The schema may default `mask: None`
@@ -234,10 +292,15 @@ export function useConfigOverride({
       collapseEmpty(normalizedGlobalValue),
       hiddenFields,
     );
-    const collapsedCamera = stripHiddenPaths(
+    const collapsedCameraRaw = stripHiddenPaths(
       collapseEmpty(normalizedCameraValue),
       hiddenFields,
     );
+    const collapsedCamera = stripAutoDerivedMissingFromGlobal(
+      sectionPath,
+      collapsedGlobal,
+      collapsedCameraRaw,
+    );
 
     const comparisonGlobal = compareFields
       ? pickFields(collapsedGlobal, compareFields)
@@ -258,6 +321,20 @@ export function useConfigOverride({
       const globalFieldValue = get(normalizedGlobalValue, fieldPath);
       const cameraFieldValue = get(normalizedCameraValue, fieldPath);
 
+      if (
+        isAutoDerivedMissingFromGlobal(
+          sectionPath,
+          fieldPath,
+          normalizedGlobalValue,
+        )
+      ) {
+        return {
+          isOverridden: false,
+          globalValue: globalFieldValue,
+          cameraValue: cameraFieldValue,
+        };
+      }
+
       return {
         isOverridden: !isEqual(
           collapseEmpty(globalFieldValue as JsonValue),
@@ -367,10 +444,15 @@ export function useAllCameraOverrides(
         collapseEmpty(globalValue),
         hiddenFields,
       );
-      const collapsedCamera = stripHiddenPaths(
+      const collapsedCameraRaw = stripHiddenPaths(
         collapseEmpty(cameraValue),
         hiddenFields,
       );
+      const collapsedCamera = stripAutoDerivedMissingFromGlobal(
+        key,
+        collapsedGlobal,
+        collapsedCameraRaw,
+      );
       const comparisonGlobal = compareFields
         ? pickFields(collapsedGlobal, compareFields)
         : collapsedGlobal;
@@ -615,7 +697,11 @@ export function useCamerasOverridingSection(
       const deltasByPath = new Map<string, FieldDelta>();
 
       // 1. Camera-level overrides (uses base_config when a profile is active)
-      const cameraValue = collapseEmpty(cameraSectionValues[idx]);
+      const cameraValue = stripAutoDerivedMissingFromGlobal(
+        sectionPath,
+        globalValue,
+        collapseEmpty(cameraSectionValues[idx]),
+      );
       for (const delta of collectFieldDeltas(
         globalValue,
         cameraValue,
@@ -696,9 +782,13 @@ export function useCameraSectionDeltas(
     const globalValue = collapseEmpty(
       getEffectiveGlobalBaseline(config, sectionPath, compareFields, schema),
     );
-    const cameraValue = collapseEmpty(
-      normalizeConfigValue(
-        getBaseCameraSectionValue(config, cameraName, sectionPath),
+    const cameraValue = stripAutoDerivedMissingFromGlobal(
+      sectionPath,
+      globalValue,
+      collapseEmpty(
+        normalizeConfigValue(
+          getBaseCameraSectionValue(config, cameraName, sectionPath),
+        ),
       ),
     );