Add note about leaf cert and Cf handling of chain expiration

Author: RebeccaTamachiro

src/content/docs/ssl/edge-certificates/custom-certificates/uploading.mdx

@@ -36,6 +36,10 @@ Each custom certificate you upload must:
 
 ## Upload a custom certificate
 
+:::caution
+When using `compatible` or `modern` [bundling](/ssl/edge-certificates/custom-certificates/bundling-methodologies), make sure to upload only the leaf certificate. This will allow Cloudflare to properly handle [intermediate and root certificates expiration](/ssl/edge-certificates/custom-certificates/bundling-methodologies/#intermediate-and-root-certificates).
+:::
+
 <Tabs syncKey="dashPlusAPI"> <TabItem label="Dashboard">
 
 To upload a custom SSL certificate in the dashboard: