https://github.com/scipy/scipy/pull/21069

Index: scipy/_lib/_uarray/small_dynamic_array.h
--- scipy/_lib/_uarray/small_dynamic_array.h.orig
+++ scipy/_lib/_uarray/small_dynamic_array.h
@@ -142,7 +142,7 @@ class SmallDynamicArray { (public)
 
     clear();
 
-    size_ = copy.size;
+    size_ = copy.size_;
     try {
       allocate();
     } catch (...) {
