Hello Miriam, if possible, you could install the additional package systemd-coredump. Then in the output of 'journalctl --no-pager' at the bottom should the known 'segfault at' line appear. This and the following lines at that time would be of interest.
This would get better if the additional nfs-common-dbgsym could be installed  (from a separate repo). If additonal to the above steps the package gdb is installed, 'coredumpctl gdb' with the command 'bt full' at the gdb prompt would yield even better information. Kind regards, Bernhard  https://wiki.debian.org/HowToGetABacktrace#Installing_the_debugging_symbols