diff --git a/libraries/AC_Avoidance/AP_OADijkstra.cpp b/libraries/AC_Avoidance/AP_OADijkstra.cpp
index f5150cd6ea32c..8fd4d18fb2445 100644
--- a/libraries/AC_Avoidance/AP_OADijkstra.cpp
+++ b/libraries/AC_Avoidance/AP_OADijkstra.cpp
@@ -313,7 +313,7 @@ bool AP_OADijkstra::check_inclusion_polygon_updated() const
 
 // create polygons inside the existing inclusion polygons
 // returns true on success.  returns false on failure and err_id is updated
-bool AP_OADijkstra::create_inclusion_polygon_with_margin(float margin_cm, AP_OADijkstra_Error &err_id)
+bool AP_OADijkstra::_create_inclusion_polygon_with_margin(float margin_cm, AP_OADijkstra_Error &err_id)
 {
     const AC_Fence *fence = AC_Fence::get_singleton();
 
@@ -324,6 +324,8 @@ bool AP_OADijkstra::create_inclusion_polygon_with_margin(float margin_cm, AP_OAD
 
     // skip unnecessary retry to build inclusion polygon if previous fence points have not changed 
     if (_inclusion_polygon_update_ms == fence->polyfence().get_inclusion_polygon_update_ms()) {
+        // return the error code we returned last time we were called with this fence set:
+        err_id = last_create_inclusion_polygon_with_margin_error_id;
         return false;
     }
 
@@ -399,6 +401,12 @@ bool AP_OADijkstra::create_inclusion_polygon_with_margin(float margin_cm, AP_OAD
     }
     return true;
 }
+bool AP_OADijkstra::create_inclusion_polygon_with_margin(float margin_cm, AP_OADijkstra_Error &err_id)
+{
+    const bool ret = _create_inclusion_polygon_with_margin(margin_cm, err_id);
+    last_create_inclusion_polygon_with_margin_error_id = err_id;
+    return ret;
+}
 
 // check if exclusion polygons have been updated since create_exclusion_polygon_with_margin was run
 // returns true if changed
diff --git a/libraries/AC_Avoidance/AP_OADijkstra.h b/libraries/AC_Avoidance/AP_OADijkstra.h
index b0beeea2113fe..f8afe8db4c7d2 100644
--- a/libraries/AC_Avoidance/AP_OADijkstra.h
+++ b/libraries/AC_Avoidance/AP_OADijkstra.h
@@ -76,6 +76,10 @@ class AP_OADijkstra {
     // create polygons inside the existing inclusion polygons
     // returns true on success.  returns false on failure and err_id is updated
     bool create_inclusion_polygon_with_margin(float margin_cm, AP_OADijkstra_Error &err_id);
+    // create polygons inside the existing inclusion polygons
+    // returns true on success.  returns false on failure and err_id is updated.  This function is wrapped so we can remember the error ID.
+    bool _create_inclusion_polygon_with_margin(float margin_cm, AP_OADijkstra_Error &err_id);
+    AP_OADijkstra_Error last_create_inclusion_polygon_with_margin_error_id;
 
     //
     // exclusion polygon methods