diff --git a/pmd-java/etc/grammar/Java.jjt b/pmd-java/etc/grammar/Java.jjt
index e9eaacf5e5..f455a765e6 100644
--- a/pmd-java/etc/grammar/Java.jjt
+++ b/pmd-java/etc/grammar/Java.jjt
@@ -953,7 +953,7 @@ TOKEN :
    "\u1310","\u1312"-"\u1315","\u1318"-"\u131e","\u1320"-"\u1346","\u1348"-"\u135a",
    "\u13a0"-"\u13f4","\u1401"-"\u166c","\u166f"-"\u1676","\u1681"-"\u169a","\u16a0"-"\u16ea",
    "\u1780"-"\u17b3","\u17db","\u1820"-"\u1877","\u1880"-"\u18a8","\u1e00"-"\u1e9b",
-   "\u1ea0"-"\u1ef9","\u1f00"-"\u1f15","\u1f18"-"\u1f1d","\u1f20"-"\u1f45","\u1f48"-"\u1f4d",
+   "\u1ea0"-"\u1ef9","\u1d00"-"\u1d7f","\u1f00"-"\u1f15","\u1f18"-"\u1f1d","\u1f20"-"\u1f45","\u1f48"-"\u1f4d",
    "\u1f50"-"\u1f57","\u1f59","\u1f5b","\u1f5d","\u1f5f"-"\u1f7d","\u1f80"-"\u1fb4",
    "\u1fb6"-"\u1fbc","\u1fbe","\u1fc2"-"\u1fc4","\u1fc6"-"\u1fcc","\u1fd0"-"\u1fd3",
    "\u1fd6"-"\u1fdb","\u1fe0"-"\u1fec","\u1ff2"-"\u1ff4","\u1ff6"-"\u1ffc","\u203f"-"\u2040",
@@ -1022,7 +1022,7 @@ TOKEN :
    "\u12f0"-"\u130e","\u1310","\u1312"-"\u1315","\u1318"-"\u131e","\u1320"-"\u1346",
    "\u1348"-"\u135a","\u1369"-"\u1371","\u13a0"-"\u13f4","\u1401"-"\u166c","\u166f"-"\u1676",
    "\u1681"-"\u169a","\u16a0"-"\u16ea","\u1780"-"\u17d3","\u17db","\u17e0"-"\u17e9",
-   "\u180b"-"\u180e","\u1810"-"\u1819","\u1820"-"\u1877","\u1880"-"\u18a9","\u1e00"-"\u1e9b",
+   "\u180b"-"\u180e","\u1810"-"\u1819","\u1820"-"\u1877","\u1880"-"\u18a9","\u1d00"-"\u1d7f","\u1e00"-"\u1e9b",
    "\u1ea0"-"\u1ef9","\u1f00"-"\u1f15","\u1f18"-"\u1f1d","\u1f20"-"\u1f45","\u1f48"-"\u1f4d",
    "\u1f50"-"\u1f57","\u1f59","\u1f5b","\u1f5d","\u1f5f"-"\u1f7d","\u1f80"-"\u1fb4",
    "\u1fb6"-"\u1fbc","\u1fbe","\u1fc2"-"\u1fc4","\u1fc6"-"\u1fcc","\u1fd0"-"\u1fd3",
diff --git a/pmd-java/src/test/java/net/sourceforge/pmd/lang/java/ast/ParserCornersTest.java b/pmd-java/src/test/java/net/sourceforge/pmd/lang/java/ast/ParserCornersTest.java
index ef40440835..8f513b2690 100644
--- a/pmd-java/src/test/java/net/sourceforge/pmd/lang/java/ast/ParserCornersTest.java
+++ b/pmd-java/src/test/java/net/sourceforge/pmd/lang/java/ast/ParserCornersTest.java
@@ -128,6 +128,12 @@ public class ParserCornersTest {
         java7.parse(GENERICS_PROBLEM);
     }
 
+    @Test
+    public void testUnicodeIndent() {
+        // https://github.com/pmd/pmd/issues/3423
+        java7.parseResource("UnicodeIndent.java");
+    }
+
     @Test
     public void testParsersCases15() {
         java5.parseResource("ParserCornerCases.java");
diff --git a/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/ast/UnicodeIndent.java b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/ast/UnicodeIndent.java
new file mode 100644
index 0000000000..d6cbab3b84
--- /dev/null
+++ b/pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/ast/UnicodeIndent.java
@@ -0,0 +1,18 @@
+/*
+ * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+ */
+
+// https://github.com/pmd/pmd/issues/3423
+
+package com.example.pmdtest;
+
+public class PmdTest {
+
+    private static final int lᵤ = 1;
+    private static final int μᵤ = 2;
+
+    public static void main(String[] args) {
+        System.out.println(lᵤ + μᵤ);
+    }
+
+}