diff --git a/app/assets/javascripts/copy_as_gfm.js.es6 b/app/assets/javascripts/copy_as_gfm.js.es6
index 38ec6e4732ae7e6684a1fa43428b601472b62fba..0d1e9b0a9525d09216f8e2eab27d244890ba7387 100644
--- a/app/assets/javascripts/copy_as_gfm.js.es6
+++ b/app/assets/javascripts/copy_as_gfm.js.es6
@@ -89,7 +89,7 @@
     SyntaxHighlightFilter: {
       'pre.code.highlight'(el, text) {
         let lang = el.getAttribute('lang');
-        if (lang === 'text') {
+        if (lang === 'plaintext') {
           lang = '';
         }
         return '```' + lang + '\n' + text.trim() + '\n```';
diff --git a/lib/banzai/filter/syntax_highlight_filter.rb b/lib/banzai/filter/syntax_highlight_filter.rb
index 933103abb92adfc31ba8b83488405485e717ffa8..a447e2b8bff1332869775c3168d1e18f26f39084 100644
--- a/lib/banzai/filter/syntax_highlight_filter.rb
+++ b/lib/banzai/filter/syntax_highlight_filter.rb
@@ -27,6 +27,7 @@ module Banzai
 
           css_classes << " js-syntax-highlight #{lang}"
         rescue
+          lang = nil
           # Gracefully handle syntax highlighter bugs/errors to ensure
           # users can still access an issue/comment/etc.
         end
diff --git a/spec/lib/banzai/filter/syntax_highlight_filter_spec.rb b/spec/lib/banzai/filter/syntax_highlight_filter_spec.rb
index d265d29ee86990066e43a29b2c23ce551e854480..69e3c52b35af00df2089e326930896447a325ea2 100644
--- a/spec/lib/banzai/filter/syntax_highlight_filter_spec.rb
+++ b/spec/lib/banzai/filter/syntax_highlight_filter_spec.rb
@@ -6,21 +6,21 @@ describe Banzai::Filter::SyntaxHighlightFilter, lib: true do
   context "when no language is specified" do
     it "highlights as plaintext" do
       result = filter('<pre><code>def fun end</code></pre>')
-      expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" v-pre="true"><code>def fun end</code></pre>')
+      expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code>def fun end</code></pre>')
     end
   end
 
   context "when a valid language is specified" do
     it "highlights as that language" do
       result = filter('<pre><code class="ruby">def fun end</code></pre>')
-      expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight ruby" v-pre="true"><code><span class="k">def</span> <span class="nf">fun</span> <span class="k">end</span></code></pre>')
+      expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight ruby" lang="ruby" v-pre="true"><code><span class="k">def</span> <span class="nf">fun</span> <span class="k">end</span></code></pre>')
     end
   end
 
   context "when an invalid language is specified" do
     it "highlights as plaintext" do
       result = filter('<pre><code class="gnuplot">This is a test</code></pre>')
-      expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" v-pre="true"><code>This is a test</code></pre>')
+      expect(result.to_html).to eq('<pre class="code highlight js-syntax-highlight plaintext" lang="plaintext" v-pre="true"><code>This is a test</code></pre>')
     end
   end
 
@@ -31,7 +31,7 @@ describe Banzai::Filter::SyntaxHighlightFilter, lib: true do
 
     it "highlights as plaintext" do
       result = filter('<pre><code class="ruby">This is a test</code></pre>')
-      expect(result.to_html).to eq('<pre class="code highlight" v-pre="true"><code>This is a test</code></pre>')
+      expect(result.to_html).to eq('<pre class="code highlight" lang="" v-pre="true"><code>This is a test</code></pre>')
     end
   end
 end