diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index eeae8f559f4b..557af2f034ff 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -184,6 +184,8 @@ Bug Fixes
 
 * GITHUB#15939: Fix thread-safety issues with NFARunAutomaton. (Dimitris Rempapis)
 
+* GITHUB#16046: Fix double-counting of underlying Automaton in CompiledAutomaton#ramBytesUsed. (Eugene Rizhkov)
+
 Changes in Runtime Behavior
 ---------------------
 * GITHUB#14187: The query cache is now disabled by default. (Adrien Grand)
diff --git a/lucene/core/src/java/org/apache/lucene/util/automaton/CompiledAutomaton.java b/lucene/core/src/java/org/apache/lucene/util/automaton/CompiledAutomaton.java
index f414b90b3e40..5ded854f129b 100644
--- a/lucene/core/src/java/org/apache/lucene/util/automaton/CompiledAutomaton.java
+++ b/lucene/core/src/java/org/apache/lucene/util/automaton/CompiledAutomaton.java
@@ -535,8 +535,8 @@ public boolean equals(Object obj) {
 
   @Override
   public long ramBytesUsed() {
+    // this.automaton is accounted via runAutomaton.ramBytesUsed()
     return BASE_RAM_BYTES
-        + RamUsageEstimator.sizeOfObject(automaton)
         + RamUsageEstimator.sizeOfObject(commonSuffixRef)
         + RamUsageEstimator.sizeOfObject(runAutomaton)
         + RamUsageEstimator.sizeOfObject(nfaRunAutomaton)