On Emacs 29.2, using erc-5.6snapshot0.20240310.61129: 1. Enable the irccontrols module (for erc) 2. Enable `erc-interpret-mirc-color' 3. Login onto any IRC network, any channel, or perform a /query session 4. Either send, or have someone send you the string ^C99,4Text with a red background^C (Key sequence: C-q C-c 99,4Text with a red background C-q C-c) According to https://modern.ircdocs.horse/formatting.html the text *should* get formatted with a default foreground, and a red background. The observed behavior - however - is that the text is formatted with multiple background "bg" faces: (erc-control-default-bg bg:erc-color-face4 erc-input-face). A screenshot illustrating the issue is attached to this message. In GNU Emacs 29.2 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.24.20, cairo version 1.16.0) of 2024-03-13 built on lcy02-amd64-051 Repository revision: 900dc1b4bf3011e685a1ec7d7ce4dcd0262ec880 Repository branch: master Windowing system distributor 'The X.Org Foundation', version 11.0.12201001 System Description: Ubuntu 22.04.4 LTS Configured using: 'configure --prefix=/snap/emacs/current/usr --with-x-toolkit=gtk3 --without-xaw3d --with-modules --with-cairo --with-native-compilation=aot --without-pgtk --with-xinput2 --with-tree-sitter --with-json 'CFLAGS=-isystem/build/emacs/parts/emacs/install/usr/include -isystem/build/emacs/parts/emacs/install/usr/include/x86_64-linux-gnu -isystem/build/emacs/stage/usr/include -O2' 'CPPFLAGS=-isystem/build/emacs/parts/emacs/install/usr/include -isystem/build/emacs/parts/emacs/install/usr/include/x86_64-linux-gnu -isystem/build/emacs/stage/usr/include' 'LDFLAGS=-L/build/emacs/parts/emacs/install/lib -L/build/emacs/parts/emacs/install/usr/lib -L/build/emacs/parts/emacs/install/lib/x86_64-linux-gnu -L/build/emacs/parts/emacs/install/usr/lib/x86_64-linux-gnu -L/build/emacs/stage/usr/lib'' Configured features: ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD 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 $LANG: de_DE.UTF-8 value of $XMODIFIERS: @im=ibus locale-coding-system: utf-8-unix Major mode: Group Minor modes in effect: gnus-undo-mode: t shell-dirtrack-mode: t erc-ring-mode: t erc-notifications-mode: t erc-netsplit-mode: t erc-menu-mode: t erc-list-mode: t erc-irccontrols-mode: t erc-keep-place-mode: t erc-move-to-prompt-mode: t erc-readonly-mode: t erc-scrolltobottom-mode: t erc-imenu-mode: t erc-button-mode: t erc-fill-mode: t erc-stamp-mode: t erc-bufbar-mode: t erc-track-mode: t erc-match-mode: t erc-autojoin-mode: t erc-autoaway-mode: t recentf-mode: t pixel-scroll-precision-mode: t minibuffer-depth-indicate-mode: t global-whitespace-mode: t global-goto-address-mode: t goto-address-mode: t global-auto-revert-mode: t fido-vertical-mode: t icomplete-vertical-mode: t icomplete-mode: t fido-mode: t erc-networks-mode: t desktop-save-mode: t windmove-mode: t tooltip-mode: t global-eldoc-mode: t show-paren-mode: t electric-indent-mode: t mouse-wheel-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t buffer-read-only: t column-number-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 Features: (shadow emacsbug mailalias smtpmail ispell cl-print help-fns radix-tree sort smiley gnus-cite mail-extr textsec uni-scripts idna-mapping ucs-normalize uni-confusable textsec-check gnus-bcklg gnus-async gnus-ml nndraft nnmh nnfolder utf-7 rfc2104 network-stream nsm gnus-agent gnus-srvr gnus-score score-mode nnvirtual gnus-msg nntp gnus-cache display-line-numbers org-element org-persist org-id org-refile avl-tree generator oc-basic ol-eww eww url-queue mm-url ol-rmail ol-mhe ol-irc ol-info ol-gnus nnselect gnus-art mm-uu mml2015 mm-view mml-smime smime gnutls dig gnus-sum shr pixel-fill kinsoku url-file svg dom gnus-group gnus-undo gnus-start gnus-dbus gnus-cloud nnimap nnmail mail-source utf7 nnoo gnus-spec gnus-int gnus-range message sendmail yank-media puny rfc822 mml mml-sec epa epg rfc6068 epg-config mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev gmm-utils mailheader gnus-win gnus nnheader gnus-util text-property-search mail-utils range mm-util mail-prsvr ol-docview doc-view jka-compr image-mode exif dired dired-loaddefs ol-bibtex bibtex ol-bbdb ol-w3m ol-doi org-link-doi org ob ob-tangle ob-ref ob-lob ob-table ob-exp org-macro org-src ob-comint org-pcomplete org-list org-footnote org-faces org-entities noutline outline ob-emacs-lisp ob-core ob-eval org-cycle org-table ol org-fold org-fold-core org-keys oc org-loaddefs find-func cal-menu calendar cal-loaddefs org-version org-compat org-macs tramp-cache time-stamp tramp-sh tramp tramp-loaddefs trampver tramp-integration files-x tramp-compat shell parse-time iso8601 disp-table erc-ring erc-desktop-notifications notifications dbus xml erc-nicks color erc-netsplit erc-menu erc-list erc-goodies erc-imenu imenu erc-pcomplete time-date pcomplete comint ansi-osc ansi-color erc-button erc-fill erc-stamp erc-status-sidebar erc-track erc-match erc-join erc-autoaway leuven-dark-theme recentf tree-widget wid-edit pixel-scroll cua-base ring mb-depth whitespace goto-addr thingatpt autorevert filenotify icomplete erc derived format-spec erc-backend erc-networks easy-mmode erc-common inline erc-compat pcase compat erc-loaddefs desktop frameset cus-load windmove xdg site-start comp comp-cstr warnings icons rx cl-extra help-mode erc-autoloads info compat-autoloads markdown-mode-autoloads package browse-url url url-proxy url-privacy url-expand url-methods url-history url-cookie generate-lisp-file url-domsuf url-util mailcap url-handlers url-parse auth-source cl-seq eieio eieio-core cl-macs password-cache json subr-x map byte-opt gv bytecomp byte-compile url-vars cl-loaddefs cl-lib 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 lcms2 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 615423 61113) (symbols 48 32158 26) (strings 32 117195 5131) (string-bytes 1 3518684) (vectors 16 71836) (vector-slots 8 1268576 98438) (floats 8 591 755) (intervals 56 1811 223) (buffers 984 22))