diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index f338b9bf453..43fe2dd196d 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -4188,8 +4188,8 @@ a submatch 1, then completion can add something at (match-end 1).
 This is used when the delimiter needs to be of size zero (e.g. the transition
 from lowercase to uppercase characters).")
 
-(defun completion-pcm--prepare-delim-re (delims)
-  (setq completion-pcm--delim-wild-regex (concat "[" delims "*]")))
+(defun completion-pcm--delim-re (delims)
+  (concat "[" delims "*]"))
 
 (defcustom completion-pcm-word-delimiters "-_./:| "
   "A string of characters treated as word delimiters for completion.
@@ -4202,7 +4202,8 @@ expression (not containing character ranges like `a-z')."
   :set (lambda (symbol value)
          (set-default symbol value)
          ;; Refresh other vars.
-         (completion-pcm--prepare-delim-re value))
+         (setq completion-pcm--delim-wild-regex
+               (completion-pcm--delim-re value)))
   :initialize 'custom-initialize-reset
   :type 'string)
 
@@ -4342,7 +4343,9 @@ one wildcard."
                 (concat
                  (when group "\\(")
                  (if (all (lambda (x) (eq x 'any-delim)) (cdr segment))
-                     (concat completion-pcm--delim-wild-regex "*?")
+                     (concat (completion-pcm--delim-re
+                              completion-pcm-word-delimiters)
+                             "*?")
                    "[^z-a]*?")
                  (when group "\\)")))))
            segments
diff --git a/test/lisp/minibuffer-tests.el b/test/lisp/minibuffer-tests.el
index 8114899c0ff..78a5261a143 100644
--- a/test/lisp/minibuffer-tests.el
+++ b/test/lisp/minibuffer-tests.el
@@ -375,6 +375,15 @@
                   '(any "A" any-delim "B" any-delim "C" any))
                  "\\`[^z-a]*?A[-_./:| *]*?B[-_./:| *]*?C[^z-a]*?")))
 
+(ert-deftest completion-pcm--test-zerowidth-delim ()
+  (let ((completion-pcm--delim-wild-regex ; Let "u8" complete to "utf-8".
+         (concat "\\(?:" completion-pcm--delim-wild-regex
+                 "\\|\\([[:alpha:]]\\)[[:digit:]]\\)")))
+    (should (equal (car (completion-try-completion
+                         "u8-d" '("utf-8-dos" "utf-8-foo-dos" "utf-8-unix")
+                         nil 4))
+                   "utf-8-dos"))))
+
 (ert-deftest completion-pcm-bug4219 ()
   ;; With `completion-ignore-case', try-completion should change the
   ;; case of existing text when the completions have different casing.