Sorry i couldn't provide you with debug level 3 logs earlier on due to an outage of our test setup.

Anyways in the meantime i reviewed the configuration file which was causing the problem. It does not seems right to make potentially massive SQL query in sync process and serialize the entire result-set to be processed in async process. So i changed the config to do the db query in async process instead. Now the problem does not happen at all and everything is OK.

My test setup is back online now, so let me know if this case interests you. I will deploy old configuration and let you test it.

Again, thank you so much for all your help and cooperation.