Neovim: reloading a file makes highlighting colors change

[EsGeh]

Information

VIM version

$ nvim -V1 -v
NVIM v0.11.4
Build type: RelWithDebInfo
LuaJIT 2.1.1761727121
Compilation: /usr/bin/cc -march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions     -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security     -fstack-clash-protection -fcf-protection     -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -g -ffile-prefix-map=/build/neovim/src=/usr/src/debug/neovim -flto=auto -O2 -g -flto=auto -fno-fat-lto-objects -Wall -Wextra -pedantic -Wno-unused-parameter -Wstrict-prototypes -std=gnu99 -Wshadow -Wconversion -Wvla -Wdouble-promotion -Wmissing-noreturn -Wmissing-format-attribute -Wmissing-prototypes -fsigned-char -fstack-protector-strong -Wno-conversion -fno-common -Wno-unused-result -Wimplicit-fallthrough -fdiagnostics-color=always  -DUNIT_TESTING -D_GNU_SOURCE -DINCLUDE_GENERATED_DECLARATIONS -DUTF8PROC_STATIC -I/usr/include/luajit-2.1 -I/usr/include -I/build/neovim/src/neovim/build/src/nvim/auto -I/build/neovim/src/neovim/build/include -I/build/neovim/src/neovim/build/cmake.config -I/build/neovim/src/neovim/src 

          System-vimrc-Datei: "$VIM/sysinit.vim"
     Voreinstellung für $VIM: "/usr/share/nvim"

Run :checkhealth for more info

Operating System: arch linux

$ uname -srvo
Linux 6.17.6-arch1-1 #1 SMP PREEMPT_DYNAMIC Wed, 29 Oct 2025 22:23:47 +0000 GNU/Linux

What went wrong

Whenever I type : e! , the syntax highlighting colors change.

Reproducing the bug

1. I open a file containing code in a programming language supported by ALE. There is beautiful syntax highlighting.
2. I reload the file using :e!. Syntax highlighting is less beautiful and detailed.

:ALEInfo

Expand

Current Filetype: prolog
Available Linters: ['prolog_lsp', 'swipl']
Enabled Linters: ['prolog_lsp']
Ignored Linters: []
Suggested Fixers:
'remove_trailing_lines' - Remove all blank lines at the end of a file.
'trim_whitespace' - Remove all trailing whitespace characters at the end of every line.

Global Variables:
let g:ale_cache_executable_check_failures = v:null
let g:ale_change_sign_column_color = v:null
let g:ale_command_wrapper = ''
let g:ale_completion_delay = 100
let g:ale_completion_enabled = 1
let g:ale_completion_max_suggestions = 50
let g:ale_disable_lsp = 'auto'
let g:ale_echo_cursor = v:true
let g:ale_echo_msg_error_str = 'Error'
let g:ale_echo_msg_format = '[%linter%]: %(code): %%s [%severity%]'
let g:ale_echo_msg_info_str = 'Info'
let g:ale_echo_msg_warning_str = 'Warning'
let g:ale_enabled = 1
let g:ale_fix_on_save = v:false
let g:ale_fixers = {}
let g:ale_history_enabled = v:true
let g:ale_info_default_mode = 'preview'
let g:ale_history_log_output = v:true
let g:ale_keep_list_window_open = 0
let g:ale_lint_delay = 200
let g:ale_lint_on_enter = v:true
let g:ale_lint_on_filetype_changed = v:true
let g:ale_lint_on_insert_leave = v:true
let g:ale_lint_on_save = v:true
let g:ale_lint_on_text_changed = 'normal'
let g:ale_linter_aliases = {}
let g:ale_linters = {'prolog': ['prolog_lsp'], 'haskell': ['cabal_ghc', 'cspell', 'ghc_mod', 'hdevtools', 'hie', 'hlint', 'hls', 'stack_build', 'stack_ghc']}
let g:ale_linters_explicit = v:false
let g:ale_linters_ignore = {}
let g:ale_list_vertical = v:false
let g:ale_list_window_size = 10
let g:ale_loclist_msg_format = '[%linter%]: %(code): %%s [%severity%]'
let g:ale_max_buffer_history_size = 20
let g:ale_max_signs = v:null
let g:ale_maximum_file_size = v:null
let g:ale_open_list = v:false
let g:ale_pattern_options = v:null
let g:ale_pattern_options_enabled = v:null
let g:ale_root = {}
let g:ale_set_balloons = v:false
let g:ale_set_highlights = v:true
let g:ale_set_loclist = v:true
let g:ale_set_quickfix = v:false
let g:ale_set_signs = v:true
let g:ale_sign_column_always = v:null
let g:ale_sign_error = v:null
let g:ale_sign_info = v:null
let g:ale_sign_offset = v:null
let g:ale_sign_style_error = v:null
let g:ale_sign_style_warning = v:null
let g:ale_sign_warning = v:null
let g:ale_sign_highlight_linenrs = v:null
let g:ale_type_map = {}
let g:ale_use_neovim_diagnostics_api = v:true
let g:ale_use_global_executables = v:null
let g:ale_virtualtext_cursor = 'all'
let g:ale_warn_about_trailing_blank_lines = v:true
let g:ale_warn_about_trailing_whitespace = v:true

Command History:

(started) ['/bin/sh', '-c', 'swipl -g ''use_module(library(lsp_server))'' -g ''lsp_server:main'' -t halt -- stdio']

Remark

Seems like some setting competes with ALEs syntax highlighting, but that's just a guess. Hints on how to debug this issue are welcome.
This bug is definitely not fatal, but quite annoying.