diff --git a/parser/src/main/java/com/microsoft/gctoolkit/parser/jvm/PreUnifiedDiarizer.java b/parser/src/main/java/com/microsoft/gctoolkit/parser/jvm/PreUnifiedDiarizer.java
index 1bf6beb6a..aa46b134e 100644
--- a/parser/src/main/java/com/microsoft/gctoolkit/parser/jvm/PreUnifiedDiarizer.java
+++ b/parser/src/main/java/com/microsoft/gctoolkit/parser/jvm/PreUnifiedDiarizer.java
@@ -228,9 +228,8 @@ public boolean diarize(String line) {
 
     @Override
     public DateTimeStamp getTimeOfFirstEvent() {
-        if (timeOfFirstEvent == null)
-            timeOfFirstEvent = new DateTimeStamp(0.0d);
-        return timeOfFirstEvent;
+        // Keep the fallback transient so a timestamp found on a later line can still be recorded.
+        return timeOfFirstEvent == null ? new DateTimeStamp(0.0d) : timeOfFirstEvent;
     }
 
     private void timeOfFirstEvent(String line) {
@@ -1047,4 +1046,5 @@ private void setGCCause(String gcCause) {
             }
         }
     }
-}
\ No newline at end of file
+}
+
diff --git a/parser/src/test/java/com/microsoft/gctoolkit/parser/PreUnifiedDiarizerTest.java b/parser/src/test/java/com/microsoft/gctoolkit/parser/PreUnifiedDiarizerTest.java
new file mode 100644
index 000000000..250e2eeab
--- /dev/null
+++ b/parser/src/test/java/com/microsoft/gctoolkit/parser/PreUnifiedDiarizerTest.java
@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+package com.microsoft.gctoolkit.parser;
+
+import com.microsoft.gctoolkit.parser.jvm.PreUnifiedDiarizer;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class PreUnifiedDiarizerTest {
+
+    @Test
+    void earlyTimestampLookupDoesNotPreventRecordingFirstEvent() {
+        PreUnifiedDiarizer diarizer = new PreUnifiedDiarizer();
+        assertEquals(0.0, diarizer.getTimeOfFirstEvent().toSeconds());
+
+        diarizer.diarize("1.250: [GC (Allocation Failure) 100K->50K(200K), 0.001 secs]");
+        assertEquals(1.250, diarizer.getTimeOfFirstEvent().toSeconds());
+        assertEquals(1.250, diarizer.getDiary().getTimeOfFirstEvent().toSeconds());
+
+        diarizer.diarize("2.500: [GC (Allocation Failure) 100K->50K(200K), 0.001 secs]");
+        assertEquals(1.250, diarizer.getTimeOfFirstEvent().toSeconds());
+        assertEquals(1.250, diarizer.getDiary().getTimeOfFirstEvent().toSeconds());
+    }
+}