I have a customer defined idoc, when it comes into the inbound queue it get's status 64 - "IDoc ready to be transferred to application", and a job is generated for the processing instead of just immidiate processing.
It's important to mention that the partner profile configuration is set to immidiate processing.
Why does this happen and how do I change this situation ?
As you have mentioned that you are using custom defined iDoc, you might be using a custom defined BAPI to receive the data from the iDoc.
As you have said that the status is 64, your iDoc has entered the system & it has failed only when the data being sent to the application.
kindly, check if the custom defined BAPI or RFC is working fine & whether it updates the status record or not? because you custom BAPI will be receiving the data from the iDoc.
Also, test the scenario using the transaction WE19.
or else you can use manual processing of iDoc using T.code - BD87.