Simpler reproducer which will not cause a crash:
$ cat test.service [Unit] Description=test
[Service] ExecStart=/bin/sh -ec '\ true \ $Y'
$ sudo systemd-analyze verify test.service Assertion 'current[*l + 1] == quotechars[0]' failed at ../src/shared/util.c:583, function split(). Aborting.
Simpler reproducer which will not cause a crash:
$ cat test.service
[Unit]
Description=test
[Service]
ExecStart=/bin/sh -ec '\
true \
$Y'
$ sudo systemd-analyze verify test.service shared/ util.c: 583, function split(). Aborting.
Assertion 'current[*l + 1] == quotechars[0]' failed at ../src/