diff --git a/lib/fluent/plugin/filter_concat.rb b/lib/fluent/plugin/filter_concat.rb
index 6905599..c12c524 100644
--- a/lib/fluent/plugin/filter_concat.rb
+++ b/lib/fluent/plugin/filter_concat.rb
@@ -50,11 +50,10 @@ class TimeoutError < StandardError
 
     def initialize
       super
-
       @buffer = Hash.new {|h, k| h[k] = [] }
       @timeout_map_mutex = Thread::Mutex.new
       @timeout_map_mutex.synchronize do
-        @timeout_map = Hash.new {|h, k| h[k] = Fluent::Engine.now }
+        @timeout_map = Hash.new {|h, k| h[k] = time_event_now }
       end
     end
 
@@ -241,7 +240,7 @@ def process(tag, time, record)
         end
       end
       @timeout_map_mutex.synchronize do
-        @timeout_map[stream_identity] = Fluent::Engine.now
+        @timeout_map[stream_identity] = time_event_now
       end
       case @mode
       when :line
@@ -389,7 +388,7 @@ def flush_buffer(stream_identity, new_element = nil)
     end
 
     def flush_timeout_buffer
-      now = Fluent::Engine.now
+      now = time_event_now
       timeout_stream_identities = []
       @timeout_map_mutex.synchronize do
         @timeout_map.each do |stream_identity, previous_timestamp|
@@ -432,5 +431,11 @@ def handle_timeout_error(tag, time, record, message)
         router.emit_error_event(tag, time, record, TimeoutError.new(message))
       end
     end
+
+    def time_event_now
+      now = Process.clock_gettime(Process::CLOCK_REALTIME, :nanosecond)
+      Fluent::EventTime.new(now / 1_000_000_000, now % 1_000_000_000)
+    end
+
   end
 end
diff --git a/test/plugin/test_filter_concat.rb b/test/plugin/test_filter_concat.rb
index 0c765e6..e860beb 100644
--- a/test/plugin/test_filter_concat.rb
+++ b/test/plugin/test_filter_concat.rb
@@ -3,7 +3,7 @@
 class FilterConcatTest < Test::Unit::TestCase
   def setup
     Fluent::Test.setup
-    @time = Fluent::Engine.now
+    @time = time_event_now
   end
 
   CONFIG = %[
@@ -34,6 +34,10 @@ def filter_with_time(conf, messages, wait: nil)
     d.run(default_tag: "test") do
       sleep 0.1 # run event loop
       messages.each do |time, message|
+        now = time_event_now
+        if now < time
+          sleep time-now
+        end
         d.feed(time, message)
       end
       sleep wait if wait
@@ -41,6 +45,11 @@ def filter_with_time(conf, messages, wait: nil)
     d.filtered
   end
 
+  def time_event_now
+    now = Process.clock_gettime(Process::CLOCK_REALTIME, :nanosecond)
+    Fluent::EventTime.new(now / 1_000_000_000, now % 1_000_000_000)
+  end
+
   sub_test_case "config" do
     test "empty" do
       assert_raise(Fluent::ConfigError.new("'key' parameter is required")) do
@@ -242,6 +251,43 @@ def filter_with_time(conf, messages, wait: nil)
       assert_equal([], filtered)
     end
 
+    test "timeout with timeout_label for multiline start regex" do
+      config = <<-CONFIG
+        key message
+        multiline_start_regexp /^start/
+        flush_interval 1s
+        timeout_label @TIMEOUT
+      CONFIG
+      wait = 3
+      delay_message_4_to_5 = 3
+      delay_message_5_to_6 = 1
+
+      messages = [
+        [@time, { "container_id" => "1", "message" => "start" }],
+        [@time, { "container_id" => "1", "message" => "  message 1" }],
+        [@time, { "container_id" => "1", "message" => "  message 2" }],
+        [@time, { "container_id" => "1", "message" => "starting" }],
+        [@time + delay_message_4_to_5, { "container_id" => "1", "message" => "  message 3" }],
+        [@time + delay_message_4_to_5 + delay_message_5_to_6 , { "container_id" => "1", "message" => "  message 4" }],
+      ]
+
+      filtered = filter_with_time(config, messages, wait: wait) do |d|
+        errored = { "container_id" => "1", "message" => "starting" }
+        event_router = mock(Object.new).emit("test", anything, errored)
+        mock(Fluent::Test::Driver::TestEventRouter).new(anything) { event_router }
+        #commented out due to timing inconsistency
+        #stub.proxy(d.instance).flush_timeout_buffer.times(wait + delay_message_4_to_5 + delay_message_5_to_6)
+        stub.proxy(d.instance).handle_timeout_error.times(1)
+
+      end
+      expected = [
+        [@time, { "container_id" => "1", "message" => "start\n  message 1\n  message 2" }],
+        [@time + 3, { "container_id" => "1", "message" => "  message 3" }],
+        [@time + 4, { "container_id" => "1", "message" => "  message 4" }],
+      ]
+      assert_equal(expected, filtered)
+    end
+
     test "no timeout" do
       messages = [
         { "container_id" => "1", "message" => "message 1" },
@@ -975,11 +1021,13 @@ def filter_with_time(conf, messages, wait: nil)
         [@time + 2, { "container_id" => "1", "message" => "  message 4" }],
       ]
       filtered = filter_with_time(config, messages, wait: 3) do |d|
-        errored = { "container_id" => "1", "message" => "start\n  message 3\n  message 4" }
+        errored = { "container_id" => "1", "message" => "start" }
         mock(d.instance.router).emit_error_event("test", @time, errored, anything)
       end
       expected = [
-        [@time, { "container_id" => "1", "message" => "start\n  message 1\n  message 2" }]
+        [@time, { "container_id" => "1", "message" => "start\n  message 1\n  message 2" }],
+        [@time + 1, { "container_id" => "1", "message" => "  message 3" }],
+        [@time + 2, { "container_id" => "1", "message" => "  message 4" }],
       ]
       assert_equal(expected, filtered)
     end