--- a/lisp/window.el
+++ b/lisp/window.el
@@ -5289,12 +5289,17 @@ window--state-get-1
 		     (scroll-bars . ,(window-scroll-bars window))
 		     (vscroll . ,(window-vscroll window))
 		     (dedicated . ,(window-dedicated-p window))
-		     (point . ,(if writable point
-                                 (copy-marker point
-                                              (buffer-local-value
-                                               'window-point-insertion-type
-                                               buffer))))
-		     (start . ,(if writable start (copy-marker start)))))))))
+		     (point . ,(if writable
+                                   point
+                                 (with-current-buffer buffer
+                                   (copy-marker point
+                                                (buffer-local-value
+                                                 'window-point-insertion-type
+                                                 buffer)))))
+		     (start . ,(if writable
+                                   start
+                                 (with-current-buffer buffer
+                                   (copy-marker start))))))))))
 	 (tail
 	  (when (memq type '(vc hc))
 	    (let (list)