rhel8: The output of certain journal logs is corrupted

Issue

This is a regression issue. A malformed log output from a service unit was noticed.
One example is that when libvirt-guests.service is started, the following malformed log appears:

Nov 30 01:49:19 localhost libvirt-guests.sh[232829]: R
Nov 30 01:49:19 localhost libvirt-guests.sh[232848]: R
Nov 30 01:49:19 localhost libvirt-guests.sh[232848]: esuming guest xxxxxx:
Nov 30 01:49:19 localhost libvirt-guests.sh[232928]: esum
Nov 30 01:49:19 localhost libvirt-guests.sh[232829]: e
Nov 30 01:49:19 localhost libvirt-guests.sh[232935]: e
Nov 30 01:49:19 localhost libvirt-guests.sh[232935]: esuming guest xxxxxx:
Nov 30 01:49:19 localhost libvirt-guests.sh[233016]: esum
Nov 30 01:49:19 localhost libvirt-guests.sh[232829]: e

Although the output messages are corrupted like this, systemd-journald process receives intact messages according to strace.