diff --git a/doc/api/esm.md b/doc/api/esm.md
index f5f34c8c43ff86..0ee1717503d6ab 100644
--- a/doc/api/esm.md
+++ b/doc/api/esm.md
@@ -375,6 +375,9 @@ behind the `--experimental-import-meta-resolve` flag:
 
 * `parent` {string|URL} An optional absolute parent module URL to resolve from.
 
+> **Caveat** This feature is not available within custom loaders (it would
+> create a deadlock).
+
 ## Interoperability with CommonJS
 
 ### `import` statements