diff --git a/Library/Homebrew/cask/cask.rb b/Library/Homebrew/cask/cask.rb
index fd23cafada..89a7c19ad9 100644
--- a/Library/Homebrew/cask/cask.rb
+++ b/Library/Homebrew/cask/cask.rb
@@ -20,7 +20,7 @@ module Cask
 
     attr_reader :token, :sourcefile_path, :source, :config, :default_config
 
-    attr_accessor :download
+    attr_accessor :download, :allow_reassignment
 
     def self.all
       Tap.flat_map(&:cask_files).map do |f|
@@ -38,11 +38,12 @@ module Cask
       @tap
     end
 
-    def initialize(token, sourcefile_path: nil, source: nil, tap: nil, config: nil, &block)
+    def initialize(token, sourcefile_path: nil, source: nil, tap: nil, config: nil, allow_reassignment: false, &block)
       @token = token
       @sourcefile_path = sourcefile_path
       @source = source
       @tap = tap
+      @allow_reassignment = allow_reassignment
       @block = block
 
       @default_config = config || Config.new
diff --git a/Library/Homebrew/cask/dsl.rb b/Library/Homebrew/cask/dsl.rb
index e56bfc9a18..e4d1ac47a2 100644
--- a/Library/Homebrew/cask/dsl.rb
+++ b/Library/Homebrew/cask/dsl.rb
@@ -112,7 +112,7 @@ module Cask
     def set_unique_stanza(stanza, should_return)
       return instance_variable_get("@#{stanza}") if should_return
 
-      if instance_variable_defined?("@#{stanza}")
+      if !@cask.allow_reassignment && instance_variable_defined?("@#{stanza}")
         raise CaskInvalidError.new(cask, "'#{stanza}' stanza may only appear once.")
       end
 
@@ -137,7 +137,7 @@ module Cask
 
         return unless default
 
-        unless @language_blocks.default.nil?
+        if !@cask.allow_reassignment && @language_blocks.default.present?
           raise CaskInvalidError.new(cask, "Only one default language may be defined.")
         end
 
@@ -294,7 +294,9 @@ module Cask
       @livecheck ||= Livecheck.new(self)
       return @livecheck unless block
 
-      raise CaskInvalidError.new(cask, "'livecheck' stanza may only appear once.") if @livecheckable
+      if !@cask.allow_reassignment && @livecheckable
+        raise CaskInvalidError.new(cask, "'livecheck' stanza may only appear once.")
+      end
 
       @livecheckable = true
       @livecheck.instance_eval(&block)
diff --git a/Library/Homebrew/livecheck/strategy/extract_plist.rb b/Library/Homebrew/livecheck/strategy/extract_plist.rb
index 8bb2aeeefc..2486a545bc 100644
--- a/Library/Homebrew/livecheck/strategy/extract_plist.rb
+++ b/Library/Homebrew/livecheck/strategy/extract_plist.rb
@@ -103,14 +103,14 @@ module Homebrew
 
           match_data = { matches: {}, regex: regex, url: url }
 
-          if url && url != cask.url.to_s
-            cask_object_for_livecheck = Cask::Cask.new("livecheck-cask", config: cask.config) do
-              url url.to_s
-            end
-
-            unversioned_cask_checker = UnversionedCaskChecker.new(cask, livecheck_url: cask_object_for_livecheck)
+          unversioned_cask_checker = if url.present? && url != cask.url.to_s
+            # Create a copy of the `cask` that uses the `livecheck` block URL
+            cask_copy = Cask::CaskLoader.load(cask.full_name)
+            cask_copy.allow_reassignment = true
+            cask_copy.url { url }
+            UnversionedCaskChecker.new(cask_copy)
           else
-            unversioned_cask_checker = UnversionedCaskChecker.new(cask)
+            UnversionedCaskChecker.new(cask)
           end
 
           items = unversioned_cask_checker.all_versions.transform_values { |v| Item.new(bundle_version: v) }
diff --git a/Library/Homebrew/unversioned_cask_checker.rb b/Library/Homebrew/unversioned_cask_checker.rb
index fa85d4fc4d..af6a659573 100644
--- a/Library/Homebrew/unversioned_cask_checker.rb
+++ b/Library/Homebrew/unversioned_cask_checker.rb
@@ -15,21 +15,15 @@ module Homebrew
 
     sig {  returns(Cask::Cask) }
     attr_reader :cask
-    attr_reader :livecheck_url
 
-    sig { params(cask: Cask::Cask, livecheck_url: T.nilable(Cask::Cask)).void }
-    def initialize(cask, livecheck_url: nil)
+    sig { params(cask: Cask::Cask).void }
+    def initialize(cask)
       @cask = cask
-      @livecheck_url = livecheck_url
     end
 
     sig { returns(Cask::Installer) }
     def installer
-      @installer ||= if livecheck_url
-        Cask::Installer.new(livecheck_url, verify_download_integrity: false)
-      else
-        Cask::Installer.new(cask, verify_download_integrity: false)
-      end
+      @installer ||= Cask::Installer.new(cask, verify_download_integrity: false)
     end
 
     sig { returns(T::Array[Cask::Artifact::App]) }