Unable to audit systemd events

Issue

An audit rule is in place that should log events generated by systemd however it's noticed that no events with pid 1 are logged.
An example rule which will track all systemd syscalls:

# auditctl -a always,exit -S all -F pid=1 -F key=systemd
# auditctl -l
LIST_RULES: exit,always pid=1 (0x1) key=systemd syscall=all

Watch systemd to confirm syscalls are made which should generate audit events

# strace -c -p 1
Process 1 attached
^CProcess 1 detached
% time     seconds  usecs/call     calls    errors syscall
------ ----------- ----------- --------- --------- ----------------
 31.88    0.000051          13         4           epoll_wait
 26.87    0.000043          22         2           read
 11.25    0.000018           9         2           open
 10.62    0.000017           9         2           munmap
  9.38    0.000015           2         8         2 recvmsg
  6.25    0.000010           5         2           mmap
  1.88    0.000003           2         2           close
  1.88    0.000003           2         2           timerfd_settime
  0.00    0.000000           0         2           fstat
  0.00    0.000000           0         4           clock_gettime
------ ----------- ----------- --------- --------- ----------------
100.00    0.000160                    30         2 total

o But no new audit events with our key are logged since the rule was added:

# ausearch -ts recent -k systemd
<no matches>