bash script calling rdiff-backup never ends - sh

Question

I want to run rdiff-backup and then switch of the raspberrypi it was running on.
I use the following script:
#!/bin/sh
date > /home/mik/rdiff-backup.log
echo "rsync start" >> /home/mik/rdiff-backup.log
rdiff-backup -v5 --print-statistics offlinebackup#server::/srv/backup /srv/datenserverBackup/backup >> /home/mik/rdiff-backup.log 2>&1
sync
date >> /home/mik/rdiff-backup.log
echo "rdiff-backup end" >> /home/mik/rdiff-backup.log
df -h >> /home/mik/rdiff-backup.log
sync
halt
The log file looks good (for the rdiff-backup part):
Sat 12 Aug 08:20:59 UTC 2017
rsync start
Unable to import win32security module. Windows ACLs
not supported by filesystem at /srv/backup
escape_dos_devices not required by filesystem at /srv/backup
Warning: name offlinebackup not found on system, dropping ACL entry.
Further ACL entries dropped with this name will not trigger further warnings
Using rdiff-backup version 1.2.8
Executing ssh -C offlinebackup#server rdiff-backup --server
-----------------------------------------------------------------
Detected abilities for source (read only) file system:
Access control lists On
Extended attributes On
Windows access control lists Off
Case sensitivity On
Escape DOS devices Off
Escape trailing spaces Off
Mac OS X style resource forks Off
Mac OS X Finder information Off
-----------------------------------------------------------------
Unable to import win32security module. Windows ACLs
not supported by filesystem at /srv/datenserverBackup/backup/rdiff-backup-data/rdiff-backup.tmp.0
escape_dos_devices not required by filesystem at /srv/datenserverBackup/backup/rdiff-backup-data/rdiff-backup.tmp.0
-----------------------------------------------------------------
Detected abilities for destination (read/write) file system:
Ownership changing On
Hard linking On
fsync() directories On
Directory inc permissions On
High-bit permissions On
Symlink permissions Off
Extended filenames On
Windows reserved filenames Off
Access control lists On
Extended attributes On
Windows access control lists Off
Case sensitivity On
Escape DOS devices Off
Escape trailing spaces Off
Mac OS X style resource forks Off
Mac OS X Finder information Off
-----------------------------------------------------------------
Backup: must_escape_dos_devices = 0
Starting increment operation /srv/backup to /srv/datenserverBackup/backup
Processing changed file .
Incrementing mirror file /srv/datenserverBackup/backup
Processing changed file abc
Incrementing mirror file /srv/datenserverBackup/backup/abc
Processing changed file abc/def
Incrementing mirror file /srv/datenserverBackup/backup/abc/def
Processing changed file abc/def/testfile.dxf
Incrementing mirror file /srv/datenserverBackup/backup/abc/def/testfile.dxf
--------------[ Session statistics ]--------------
StartTime 1502526061.00 (Sat Aug 12 08:21:01 2017)
EndTime 1502527913.72 (Sat Aug 12 08:51:53 2017)
ElapsedTime 1852.72 (30 minutes 52.72 seconds)
SourceFiles 151099
SourceFileSize 386321558216 (360 GB)
MirrorFiles 151097
MirrorFileSize 386321447731 (360 GB)
NewFiles 2
NewFileSize 110485 (108 KB)
DeletedFiles 0
DeletedFileSize 0 (0 bytes)
ChangedFiles 1
ChangedSourceSize 0 (0 bytes)
ChangedMirrorSize 0 (0 bytes)
IncrementFiles 4
IncrementFileSize 0 (0 bytes)
TotalDestinationSizeChange 110485 (108 KB)
Errors 0
--------------------------------------------------
The backup is working, but then the script ends right there.
rdiff-backup.log contains the full report of rdiff-backup. But neither the line "rdiff-backup end", nor the output of "df -h".
How can I make it ran to the end?
Thanks for your answers

Answer 1

I finally found a workaround, that solves my problem.
My sciprt which is called after booting from /etc/init.d is calling the other script which does the actual work (i.e. backup my data, and write the log file) as a background task.
/etc/init.d/CallAfterBoot.sh
#!/bin/sh
sleep 30
/home/me/DoBackup.sh & # '&' starts the script in background
/home/me/DoBackup.sh is the script I posted above which is now runing correctly.
Same script running as the same user now behaves differently. There's got to be some bug somewhere, however, it works for me now.