When headline cycle expanding on STATE is `subtree` in function `org-cycle-display-link-previews`, assume I have org-mode content like bellowing:

#+begin_src org

** TODO iamtxt.com
DEADLINE: <2025-01-17 Fri>
:LOGBOOK:
- State "TODO"       from              [2025-01-17 Fri 00:19]
:END:

https://www.iamtxt.com/book/47744.html
https://www.iamtxt.com/book/47681.html

*** kk

https://www.iamtxt.com/book/41334.html
https://www.iamtxt.com/book/42259.html

#+end_src

The first two links will be previewed twice. (I use package "org-link-beautify.el" which display icon on link. Then it will link previewing with two icons.)

So checked source code in `org-link-preview-region`. It should check whether already has org-mode link preview overlay.

For example, adding a condition outside of the `while-let*` binding code.

#+begin_src diff

modified    lisp/ol.el
@@ -2056,25 +2056,26 @@ buffer boundaries with possible narrowing."
       ;; Collect links to preview
       (while (re-search-forward org-link-any-re end t)
         (forward-char -1)               ;ensure we are on the link
-        (when-let*
-            ((link (org-element-lineage (org-element-context) 'link t))
-             (linktype (org-element-property :type link))
-             (preview-func (org-link-get-parameter linktype :preview))
-             (path (and (or include-linked
-                            (not (org-element-contents-begin link)))
-                        (org-element-property :path link))))
-          ;; Create an overlay to hold the preview
-          (let ((ov (make-overlay
-                     (org-element-begin link)
-                     (progn
-       (goto-char
- (org-element-end link))
-       (unless (eolp) (skip-chars-backward " \t"))
-       (point)))))
-            (overlay-put ov 'modification-hooks
-                         (list 'org-link-preview--remove-overlay))
-            (push ov org-link-preview-overlays)
-            (push (list preview-func ov path link) preview-queue))))
+        (unless (overlays-at (point)) ;; <-------------- Added condition here. (I think the condition can be more explicit detect on org-mode link preview property detection)
+          (when-let*
+              ((link (org-element-lineage (org-element-context) 'link t))
+               (linktype (org-element-property :type link))
+               (preview-func (org-link-get-parameter linktype :preview))
+               (path (and (or include-linked
+                              (not (org-element-contents-begin link)))
+                          (org-element-property :path link))))
+            ;; Create an overlay to hold the preview
+            (let ((ov (make-overlay
+                       (org-element-begin link)
+                       (progn
+         (goto-char
+  (org-element-end link))
+         (unless (eolp) (skip-chars-backward " \t"))
+         (point)))))
+              (overlay-put ov 'modification-hooks
+                           (list 'org-link-preview--remove-overlay))
+              (push ov org-link-preview-overlays)
+              (push (list preview-func ov path link) preview-queue)))))
       ;; Collect previews in buffer-local LIFO preview queue
       (setq org-link-preview--queue
             (nconc (nreverse preview-queue) org-link-preview--queue))

#+end_src