Hi,
Bacula will not re-backup the 4 jobs on the tape unless you have a schedule for that or run them manually.
If would recommend you rewind/weof the tape and relabel it before reuse this tape in Bacula.
You can use bls/bextract to restore the data there to another place and then save them again in the same tape (after rewind/weof/label) or a new one.
Best regards,
Ana