diff --git a/lib/jekyll/polyglot/patches/jekyll/site.rb b/lib/jekyll/polyglot/patches/jekyll/site.rb
index c1a30688f..de7576723 100644
--- a/lib/jekyll/polyglot/patches/jekyll/site.rb
+++ b/lib/jekyll/polyglot/patches/jekyll/site.rb
@@ -213,26 +213,30 @@ def absolute_url_regex(url, disabled = false)
 
     def relativize_urls(doc, regex)
       return if doc.output.nil?
-
-      doc.output.gsub!(regex, "href=\"#{@baseurl}/#{@active_lang}/" + '\1"')
+      modified_output = doc.output.dup
+      modified_output.gsub!(regex, "href=\"#{@baseurl}/#{@active_lang}/" + '\1"')
+      doc.output = modified_output
     end
 
     def relativize_absolute_urls(doc, regex, url)
       return if doc.output.nil?
-
-      doc.output.gsub!(regex, "href=\"#{url}#{@baseurl}/#{@active_lang}/" + '\1"')
+      modified_output = doc.output.dup
+      modified_output.gsub!(regex, "href=\"#{url}#{@baseurl}/#{@active_lang}/" + '\1"')
+      doc.output = modified_output
     end
 
     def correct_nonrelativized_absolute_urls(doc, regex, url)
       return if doc.output.nil?
-
-      doc.output.gsub!(regex, "href=\"#{url}#{@baseurl}/" + '\1"')
+      modified_output = doc.output.dup
+      modified_output.gsub!(regex, "href=\"#{url}#{@baseurl}/" + '\1"')
+      doc.output = modified_output
     end
 
     def correct_nonrelativized_urls(doc, regex)
       return if doc.output.nil?
-
-      doc.output.gsub!(regex, "href=\"#{@baseurl}/" + '\1"')
+      modified_output = doc.output.dup
+      modified_output.gsub!(regex, "href=\"#{@baseurl}/" + '\1"')
+      doc.output = modified_output
     end
   end
 end