diff --git a/Library/Homebrew/dev-cmd/bump-cask-pr.rb b/Library/Homebrew/dev-cmd/bump-cask-pr.rb
index 2bb3e15d27..7d381eab64 100644
--- a/Library/Homebrew/dev-cmd/bump-cask-pr.rb
+++ b/Library/Homebrew/dev-cmd/bump-cask-pr.rb
@@ -143,6 +143,7 @@ module Homebrew
                                                       silent:        true)
 
       tmp_cask = Cask::CaskLoader.load(tmp_contents)
+      tmp_config = cask.config
       tmp_url = tmp_cask.url.to_s
 
       if new_hash.nil?
@@ -154,9 +155,9 @@ module Homebrew
       cask.languages.each do |language|
         next if language == cask.language
 
-        tmp_cask.config.languages = [language]
-
+        lang_config = tmp_config.merge(Cask::Config.new(explicit: { languages: [language] }))
         lang_cask = Cask::CaskLoader.load(tmp_contents)
+        lang_cask.config = lang_config
         lang_url = lang_cask.url.to_s
         lang_old_hash = lang_cask.sha256