By mistake, I configured StrongSwan in such manner:
left=10.10.10.10 right=10.10.10.10
I saved file, reloaded IPSec confit and restarted StrongSwan daemon. Normally, with such configuration, I would expect some sort of errors in systemctl but StrongSwan was active and on tcpdump I could see how my IF is trying to establish IPSec connection with itself. Why StrongSwan is not validating errors in users config or why it is treating my config as valid?