bug#53896: 28.0.91; Icomplete Vertical Mode fails to preview "C-x 8 RET 8072"

[Van Ly]

The vertical listing in the minibuffer in response to "insert-char" fails to preview the 
match for "C-x 8 RET 8072".

observed behavior
* start by "emacs -Q"
* M-x customize RET
* search "icomplete vertical"
* toggle "on" Icomplete Vertical Mode 
* switch to "*scratch*" buffer
; --------------------------------
; minibuffer fails to preview 8072
; --------------------------------
* C-x 8 RET
* continue typing "80" ;; shows LINEAR A SIGN A580, A800, A801, A802, A803, 
A804, A805
* continue typing "807" ;; shows LINEAR A SIGN A807
* continue typing "8072" ;; shows "8072 [No matches]"

expected behavior
* start by "emacs -Q"
* M-x customize RET
* search "icomplete vertical"
* toggle "on" Icomplete Vertical Mode
* switch to "*scratch*" buffer
; ----------------------------------
; minibuffer previews match for 8072
; ----------------------------------
* C-x 8 RET
* continue typing "80" ;; shows LINEAR A SIGN A580, A800, A801, A802, A803, 
A804, A805
* continue typing "807" ;; shows LINEAR A SIGN A807
* continue typing "8072" ;; shows "聲 CJK IDEOGRAPH-8072"

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vl

bug-gnu-emacs-28.0.91.text
Description: 28.0.91 bug report