diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f58bfe7..9b51df4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -33,6 +33,6 @@ jobs:
         run: ruby --version; bundle exec rspec spec || $ALLOW_FAILURES
       - name: Coveralls GitHub Action
         uses: coverallsapp/github-action@v2
-        if: "matrix.ruby == '3.2'"
+        if: "matrix.ruby == '3.3'"
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/lib/sparql/grammar/parser11.rb b/lib/sparql/grammar/parser11.rb
index a2e7c25..67f3cfd 100644
--- a/lib/sparql/grammar/parser11.rb
+++ b/lib/sparql/grammar/parser11.rb
@@ -2330,6 +2330,8 @@ def iri(value)
 
     def ns(prefix, suffix)
       base = prefix(prefix).to_s
+      suffix = suffix.to_s.gsub(PN_LOCAL_ESC) {|esc| esc[1]} if
+        suffix.to_s.match?(PN_LOCAL_ESC)
       suffix = suffix.to_s.sub(/^\#/, "") if base.index("#")
       debug {"ns(#{prefix.inspect}): base: '#{base}', suffix: '#{suffix}'"}
       iri(base + suffix.to_s)