Query service and JDBC NULL value password

[Point]

Hi all,

i have a tricky problem.
- We are running windows servers, with Oracle DB as DWH.
- We have OCI en DQM (mix mode) CQM with tnsnames and JDBC via Thin client sql description.
- ACC and PROD are as setting equal as settings

Problem:
Now we are getting error sometimes 4 to 6 times a day. Where reports cannot make connection to DWH. (XQE-DS-0006, failure to login). After testing the connection i get that the OCI works but the JDBC has a null value as password and will not work.

After reset of the query service, everything works again.

(account and password are the same for OCI and JDBC). same signon.

I dont get any weird error in the log.
Some gut feeling said that because the testing the connection CQM works i think that there is something wrong in setting up the connection from the Content store to the query service for JDBC. ??

Still investigating. Any help is welcome.