diff --git a/test/plugin/in_tail/test_compatibility.rb b/test/plugin/in_tail/test_compatibility.rb
index 1a166b6550..4f55d68ab8 100644
--- a/test/plugin/in_tail/test_compatibility.rb
+++ b/test/plugin/in_tail/test_compatibility.rb
@@ -425,6 +425,8 @@ def test_receive_lines_returning_false_does_not_advance_the_position
       plugin = d.instance
       d.run do
         tw = first_watcher(plugin)
+        # Only explicit notifications should drive this test, without stat or timer callbacks.
+        tw.watchers.each { |trigger| plugin.event_loop_detach(trigger) }
         File.binwrite("#{@tmp_dir}/tail.txt", "test1\ntest2\n")
 
         tw.on_notify