bug#54031: 29.0.50; *scratch* buffer defaults to dynamic scoping when initial-major-mode 'emacs-lisp-mode

[No Wayman]

With the following minimal init.el the initial *scratch* buffer 
does not have lexical binding enabled:

(setq initial-buffer t
     initial-major-mode 'emacs-lisp-mode)

Bug, or my misunderstanding?

In GNU Emacs 29.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 
3.24.31, cairo version 1.17.4)
of 2022-02-16 built on nbook
Repository revision: 8737d79be8f82bb12ca12dc1a7de37a4d2875f39
Repository branch: master
System Description: Arch Linux

Configured using:
'configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
--localstatedir=/var --mandir=/usr/share/man 
--with-gameuser=:games
--with-sound=alsa --with-modules --without-libotf 
--without-m17n-flt
--without-gconf --without-gsettings --with-native-compilation
--with-xinput2 --with-pgtk --without-xaw3d --with-sound=no
--without-gpm --without-compress-install
'--program-transform-name=s/\([ec]tags\)/\1.emacs/'
'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fno-plt 
-fexceptions
-Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security
-fstack-clash-protection -fcf-protection'
LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now'
Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS HARFBUZZ JPEG JSON 
LCMS2
LIBSYSTEMD LIBXML2 MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PGTK 
PNG
RSVG SECCOMP SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP XIM 
GTK3 ZLIB
Important settings:
 value of $LANG: en_US.UTF-8
 locale-coding-system: utf-8-unix