Description of problem:
Found in the log:
+ce.d/timeout.conf:3: Unknown lvalue 'JobRunningTimeoutSec' in section 'Unit': 4 Time(s)
/usr/lib/systemd/system/rsyslog.service:21: Unknown lvalue 'LimitNOFILE' in section 'Install': 5
Version-Release number of selected component (if applicable):
Steps to Reproduce:
The entry is ignored
*** This bug has been marked as a duplicate of bug 1580013 ***
See 1580013 for the error about LimitNOFILE.
The first error seems to come from a version mixup (using a newer generator with an older systemd version). JobRunningTimeoutSec was added in systemd-234, which is not available in Fedora 26. I see from the kernel version that you are running some mix of F26 and F28 packages. You can ignore the error, it'll go away when you fully update.