Hello Gunnar.
Maybe you should recheck your fileset and your retention time, configured on your job´s pool settings.
When you start a job, you can see the job´s progress on the Bacula´s Cosole, by typing "status" and them selecting the client you´re backing up.
When you do this more than once, you can compare the data volume copied and see wich file is being backing up at that moment.
You can also check your database´s tables. I don´t think that´s the problem, but it´s nice to check it.
If you´re using MySql, for example, just type:
"mysql bacula"
"show tables ;"
and them check all the tables (or just the File tables) by typing "check table <TABLENAME> ;".
If something is wrong, you can repair it by typing "repair table <TABLENAME> ;"
I hope this information can help you.
Best regards
Anderson Lorente