From emacs -q, evaluate:

  (custom-set-variables '(custom-enabled-themes '(modus-vivendi)))
  (global-display-fill-column-indicator-mode 1)

Emacs will fail the eassert in append_stretch_glyph at
xdisp.c:30993. Looking at it in gdb, append_stretch_glyph is passed an
it with both ascent=descent=1 and height=11. It doesn't happen with the
default theme, nor with adwaita or leuven-dark (picked randomly), but I
haven't been able to figure out which part of the modus themes lead to
the weird ascent/descent values. This is repeatable for me, and I'm
happy to poke at it more if someone can tell me where to poke.

xbacktrace says: "redisplay_internal (C function)" (0x0)
I've attached a file that contains the full trace (apologies if gmail makes
it hard to read; let me know and I'll follow up with it inline).

In GNU Emacs 29.0.60 (build 2, x86_64-pc-linux-gnu, GTK+ Version
 3.24.24, cairo version 1.16.0) of 2023-01-04 built on penguin
Repository revision: 8d530ca6542b169cb8f0cd3862cc5d24f68935c8
Repository branch: emacs-29
Windowing system distributor 'The X.Org Foundation', version 11.0.12008000
System Description: Debian GNU/Linux 11 (bullseye)

Configured using:
 'configure -C --with-native-compilation --with-json --without-xwidgets
 --without-pop --with-small-ja-dic --without-imagemagick
 --enable-checking=yes,glyphs --enable-check-lisp-object-type=yes
 'CFLAGS=-g3 -O0''

Configured features:
CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG JSON
LIBOTF LIBSELINUX LIBXML2 M17N_FLT MODULES NATIVE_COMP NOTIFY INOTIFY
PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS
TREE_SITTER X11 XDBE XIM XINPUT2 XPM GTK3 ZLIB

Important settings:
  value of $LC_COLLATE: C
  value of $LC_CTYPE: en_US.UTF-8
  value of $LC_MESSAGES: en_US.UTF-8
  value of $LC_NUMERIC: en_US.UTF-8
  value of $LC_TIME: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: ELisp/d

Minor modes in effect:
  global-display-fill-column-indicator-mode: t
  display-fill-column-indicator-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny rfc822
mml mml-sec password-cache epa derived epg rfc6068 epg-config gnus-util
text-property-search time-date mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils dired-aux dired dired-loaddefs
easy-mmode comp comp-cstr warnings icons subr-x rx cl-seq cl-macs gv
cl-extra help-mode cl-loaddefs cl-lib bytecomp byte-compile
display-fill-column-indicator rmc iso-transl tooltip cconv eldoc paren
electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu
timer select scroll-bar mouse jit-lock font-lock syntax font-core
term/tty-colors frame minibuffer nadvice seq simple cl-generic
indonesian philippine cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
composite emoji-zwj charscript charprop case-table epa-hook
jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button loaddefs
theme-loaddefs faces cus-face macroexp files window text-properties
overlay sha1 md5 base64 format env code-pages mule custom widget keymap
hashtable-print-readable backquote threads dbusbind inotify
dynamic-setting system-font-setting font-render-setting cairo
move-toolbar gtk x-toolkit xinput2 x multi-tty make-network-process
native-compile emacs)

Memory information:
((conses 16 100278 8108)
 (symbols 48 7547 0)
 (strings 32 28488 2543)
 (string-bytes 1 881744)
 (vectors 16 20890)
 (vector-slots 8 378240 12529)
 (floats 8 36 30)
 (intervals 56 384 5)
 (buffers 984 14))