diff --git a/docs/KNOWN_BUGS b/docs/KNOWN_BUGS
index e5ff518e29..742e06f0e5 100644
--- a/docs/KNOWN_BUGS
+++ b/docs/KNOWN_BUGS
@@ -105,6 +105,7 @@ problems may have been fixed or changed somewhat since this was written.
  16.6 aws-sigv4 does not behave well with AWS VPC Lattice
 
  17. HTTP/2
+ 17.1 HTTP/2 prior knowledge over proxy
  17.2 HTTP/2 frames while in the connection pool kill reuse
  17.3 ENHANCE_YOUR_CALM causes infinite retries
 
@@ -596,6 +597,10 @@ problems may have been fixed or changed somewhat since this was written.
 
 17. HTTP/2
 
+17.1 HTTP/2 prior knowledge over proxy
+
+ https://github.com/curl/curl/issues/12641
+
 17.2 HTTP/2 frames while in the connection pool kill reuse
 
  If the server sends HTTP/2 frames (like for example an HTTP/2 PING frame) to