Confirm. The same problem in Ubuntu 18.04 Bionic with OpenVPN 2.4.4, and the same solution - had to add CAP_AUDIT_WRITE into CapabilityBoundingSet parameter in /lib/systemd/system/openvpn@.service.
Confirm. The same problem in Ubuntu 18.04 Bionic with OpenVPN 2.4.4, and the same solution - had to add CAP_AUDIT_WRITE into CapabilityBound ingSet parameter in /lib/systemd/ system/ openvpn@ .service.