Hi Vioar,
Glad you've got it all working.
When you say "job" do you mean background job (visible in SM37) ?
If you do, you need to search for background jobs that are configured to run on a specific application server by checking the settings of background jobs in table TBTCP using fields XPGTGTSYS and XPGRFCDEST.
You may find that some of the jobs have been designated to run on the old server.
If you mean TP, then it could be that TP is picking up an environment variable from somewhere, which tells it the DB hostname.
Darryl