1 files changed, 14 insertions, 1 deletions
diff --git a/src/chunk.inl b/src/chunk.inl
index 5abc1e12..bdb4f8ae 100644
--- a/src/chunk.inl
+++ b/src/chunk.inl
@@ -8,7 +8,20 @@ template<typename F> void chunk::with_scenery_bbox_update(std::size_t i, F&& fun
     static_assert(std::is_invocable_v<F>);
     static_assert(std::is_convertible_v<decltype(fun()), bool> || std::is_same_v<void, decltype(fun())>);
     if (is_passability_modified())
-        fun();
+    {
+        auto& s = scenery_at(i);
+        auto r0 = s.r;
+        bool modified = true;
+        if constexpr(!std::is_same_v<void, std::decay_t<decltype(fun())>>)
+            modified = fun();
+        else
+            fun();
+        if (r0 != s.r)
+        {
+            fm_debug_assert(modified);
+            mark_scenery_modified();
+        }
+    }
     else
     {
         bbox x0, x;