citrus: "Reply channel not set up yet" when 2 HTTP Citrus actions happen in parallel

Citrus Version 2.7.8

Expected behavior Test passes

Actual behavior Test fails

Test case description 2 logically identical async blocks with different test data, pseudo code:

async().actions(
  insert data 1 into DB,
  behaviour with HTTP receive() and respond() with HTTP 200 OK,
  DB check that a record with status "SUCCESS" exists for the test data 1
);

async().actions(
  insert data 2 into DB,
  behaviour with HTTP receive() and respond() with HTTP 200 OK,
  DB check that a record with status "SUCCESS" exists for the test data 2
);

SUT behavior:

• SUT has a background job which is triggered every 5 sec (on TEST env)
• The background job scans DB for new entries and starts processing them
• SUT then does HTTP POST with this new data as payload to an external system (Citrus HTTP mock server)
• The external system responds with some additional data (the mock replies with HTTP 200 OK)
• When SUT receives this data, the processing is finished and SUT then stores a record with status SUCCESS into DB (Citrus checks that DB has this entry at the end of the async blocks)

Note: one async block alone works but 2 blocks cause a failure:

12:57:06,068 DEBUG on.DefaultCorrelationManager| Finding correlated object for 'citrus_message_id = '9a369286-4824-4d6c-9eac-0bb12308d19a''
12:57:06,068 DEBUG           citrus.RetryLogger| Reply channel not set up yet - retrying in 500ms

It seems that Citrus cannot find the right HTTP channel for sending a response.