diff --git a/.changeset/techdocs-back-once-again.md b/.changeset/techdocs-back-once-again.md
new file mode 100644
index 0000000000..bf99f2d509
--- /dev/null
+++ b/.changeset/techdocs-back-once-again.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-techdocs': patch
+---
+
+Fixed a bug preventing custom TechDocs reader page implementations from rendering without being double-wrapped in the `<TechDocsReaderPage />` component.
diff --git a/.changeset/techdocs-renegade-master.md b/.changeset/techdocs-renegade-master.md
new file mode 100644
index 0000000000..9185faabfc
--- /dev/null
+++ b/.changeset/techdocs-renegade-master.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-techdocs': patch
+---
+
+Fixed a bug that caused addons in the `Subheader` location to break the default TechDocs reader page layout.
diff --git a/plugins/techdocs/api-report.md b/plugins/techdocs/api-report.md
index 4575ef7b28..936df8991c 100644
--- a/plugins/techdocs/api-report.md
+++ b/plugins/techdocs/api-report.md
@@ -18,7 +18,6 @@ import { PropsWithChildren } from 'react';
 import { default as React_2 } from 'react';
 import { ReactNode } from 'react';
 import { RouteRef } from '@backstage/core-plugin-api';
-import { StyledComponentProps } from '@material-ui/core';
 import { TableColumn } from '@backstage/core-components';
 import { TableProps } from '@backstage/core-components';
 import { TechDocsEntityMetadata as TechDocsEntityMetadata_2 } from '@backstage/plugin-techdocs-react';
@@ -351,15 +350,11 @@ export type TechDocsReaderPageRenderFunction = ({
 }) => JSX.Element;
 
 // @public
-export const TechDocsReaderPageSubheader: React_2.ComponentType<
-  Pick<
-    {
-      toolbarProps?: ToolbarProps<'div', {}> | undefined;
-    },
-    'toolbarProps'
-  > &
-    StyledComponentProps<'root'>
->;
+export const TechDocsReaderPageSubheader: ({
+  toolbarProps,
+}: {
+  toolbarProps?: ToolbarProps<'div', {}> | undefined;
+}) => JSX.Element | null;
 
 // @public
 export const TechDocsReaderProvider: ({