An error was encountered while opening journal file or directory

[yuwata]

https://jenkins-systemd.apps.ocp.cloud.ci.centos.org/job/upstream-vagrant-archlinux/19224/artifact/systemd-centos-ci/artifacts_xgt3kbqw/vagrant-logs.Z30/vagrant-arch-testsuite.ikV/TEST-74-AUX-UTILS_PASS.log

Spawning getter /systemd-meson-build/journalctl -o export -D /var/tmp/systemd-test-TEST-74-AUX-UTILS/root/var/log/journal...
Creating journal file /var/tmp/systemd-test-TEST-74-AUX-UTILS/system.journal on a btrfs file system, and copy-on-write is enabled. This is likely to slow down journal access substantially, please consider turning off the copy-on-write file attribute on the journal directory, using chattr +C.
An error was encountered while opening journal file or directory /var/tmp/systemd-test-TEST-74-AUX-UTILS/root/var/log/journal/dbf1d7fab5e74316bcb917b36d385481, ignoring file: No such file or directory
Finishing after writing 87967 entries
-rw-r----- 1 root root 58720256 Nov 21 09:35 /var/tmp/systemd-test-TEST-74-AUX-UTILS/system.journal

Is it safe?