diff --git a/docs/pages/product/data-modeling/reference/cube.mdx b/docs/pages/product/data-modeling/reference/cube.mdx
index e85105401c4c2..9581d56697af8 100644
--- a/docs/pages/product/data-modeling/reference/cube.mdx
+++ b/docs/pages/product/data-modeling/reference/cube.mdx
@@ -215,6 +215,12 @@ cube(`extended_order_facts`, {
 })
 ```
 
+<WarningBox>
+
+Extends using non-named cubes will not copy all fields across. For example the `refresh_key` value will not be copied and the default refresh key for the given database will be used (see `refresh_key` below for more details)
+
+</WarningBox>
+
 ### `data_source`
 
 Each cube can have its own `data_source` name to support scenarios where data
@@ -636,4 +642,4 @@ The `access_policy` parameter is used to configure [data access policies][ref-re
 [ref-ref-pre-aggs]: /product/data-modeling/reference/pre-aggregations
 [ref-ref-dap]: /product/data-modeling/reference/data-access-policies
 [ref-syntax-cube-sql]: /product/data-modeling/syntax#cubesql-function
-[ref-extension]: /product/data-modeling/concepts/code-reusability-extending-cubes
\ No newline at end of file
+[ref-extension]: /product/data-modeling/concepts/code-reusability-extending-cubes