we are using cups 1.7 (cups-1.7.5-9.1.x86_64) on SLES 12 as printserver for SAP Retail. Now we notice that when a print job is received by cups-lpd from a user which has umlauts in his SAP username the cups service terminate.
This is the last log entry in cups error_log:

add_job: requesting-user-name="VG▒BBEL"

The username should be VGÖBBEL.

/var/log/messages shows this

2015-11-27T13:34:25.786133+01:00 plato cupsd[16407]: process 16407: arguments to dbus_message_iter_append_basic() were incorrect, assertion "_dbus_check_is_valid_utf8 (*string_p)" failed in file dbus-message.c line 2676.

How can we fix this?