Funny behaviour, call-back/DISA

From an old freepbx-installation I made a configuration full-backup and use it now in a newer installation on a new installed server (which means FreePBX
The funny thing is: I deleted the old DISA and call back records, BUT after calling the new created entries the system uses an old phone number which currently dosn’t exist in the configuration.

Example: I call the new created DISA number and as a result I do not get the expected dialing tone but instead an external number will be rung!!
The DISA configuration page not even has a field for such an external number!!

So my question is why this behavior happens?
Why the PBX calls an external number (even if this is not the defined action, and the number was used some times ago in an other PBX-system)?
Is there a cache where this old number could be stored? Where I can find it in the DB?

Can anybody help?