diff --git a/src/Lucene.Net.Analysis.Common/Analysis/CommonGrams/CommonGramsFilterFactory.cs b/src/Lucene.Net.Analysis.Common/Analysis/CommonGrams/CommonGramsFilterFactory.cs
index b18756c2ce..670151703d 100644
--- a/src/Lucene.Net.Analysis.Common/Analysis/CommonGrams/CommonGramsFilterFactory.cs
+++ b/src/Lucene.Net.Analysis.Common/Analysis/CommonGrams/CommonGramsFilterFactory.cs
@@ -71,7 +71,8 @@ public virtual void Inform(IResourceLoader loader)
             }
             else
             {
-                commonWords = new CharArraySet(m_luceneMatchVersion,StopAnalyzer.ENGLISH_STOP_WORDS_SET, ignoreCase);
+                // LUCENENET-specific: backported ignoreCase fix from Lucene 8.10.0 (lucene#188, LUCENE-10008)
+                commonWords = new CharArraySet(m_luceneMatchVersion, StopAnalyzer.ENGLISH_STOP_WORDS_SET, ignoreCase);
             }
         }
 
@@ -85,4 +86,4 @@ public override TokenStream Create(TokenStream input)
             return commonGrams;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Lucene.Net.Tests.Analysis.Common/Analysis/Commongrams/TestCommonGramsFilterFactory.cs b/src/Lucene.Net.Tests.Analysis.Common/Analysis/Commongrams/TestCommonGramsFilterFactory.cs
index 5e75c52c1e..c568ffe115 100644
--- a/src/Lucene.Net.Tests.Analysis.Common/Analysis/Commongrams/TestCommonGramsFilterFactory.cs
+++ b/src/Lucene.Net.Tests.Analysis.Common/Analysis/Commongrams/TestCommonGramsFilterFactory.cs
@@ -79,6 +79,7 @@ public virtual void TestDefaults()
             AssertTokenStreamContents(stream, new string[] { "testing", "testing_the", "the", "the_factory", "factory" });
         }
 
+        // LUCENENET-specific: backported ignoreCase fix from Lucene 8.10.0 (lucene#188, LUCENE-10008)
         [Test]
         public void TestIgnoreCase()
         {
@@ -93,8 +94,9 @@ public void TestIgnoreCase()
             Tokenizer tokenizer = new MockTokenizer(new StringReader("testing The factory"),MockTokenizer.WHITESPACE, false);
             TokenStream stream = factory.Create(tokenizer);
             AssertTokenStreamContents(
-                stream, new String[] {"testing", "testing_The", "The", "The_factory", "factory"});
+                stream, new string[] {"testing", "testing_The", "The", "The_factory", "factory"});
         }
+
         /// <summary>
         /// Test that bogus arguments result in exception </summary>
         [Test]
@@ -111,4 +113,4 @@ public virtual void TestBogusArguments()
             }
         }
     }
-}
\ No newline at end of file
+}