I ran into the same issue. In my case, somehow an old (and stuck) openvpn PID was still accessing the openvpn-status.log file.
In my particular deployment, I am running two different openvpn processes simultaneously on my Ubuntu 18.04.3 server.
The issue was only seen on the openvpn-status.log file used by the first openvpn service.
I am running OpenVPN 2.4.4 server. Nothing outstanding in any of my server.conf files.
Killing the stuck PID and restarting the openvpn services fixed the issue in my case.
As a note, while monitoring the file I once saw some bytes written on it but then it quickly came back to zero size again.
user@myserver:/etc/openvpn$ ll openvpn-status.log
-rw------- 1 root root 0 Dec 27 13:55 openvpn-status.log
user@myserver:/etc/openvpn$ ll openvpn-status.log
-rw------- 1 root root 743 Dec 27 13:55 openvpn-status.log
user@myserver:/etc/openvpn$ ll openvpn-status.log
-rw------- 1 root root 0 Dec 27 13:55 openvpn-status.log
The stuck PID was 15116
user@myserver:/etc/openvpn$ sudo lsof | grep openvpn-status
openvpn 15116 nobody 5w REG 8,1 0 258326 /etc/openvpn/openvpn-status.log
openvpn 24313 nobody 4w REG 8,1 17894 287910 /etc/openvpn/openvpn-status2.log
Removing the file fixed nothing
user@myserver:/etc/openvpn$ sudo rm -f openvpn-status.log
user@myserver:/etc/openvpn$ ll openvpn-status.log
-rw------- 1 root root 0 Dec 27 13:57 openvpn-status.log
user@myserver:/etc/openvpn$ ll openvpn-status.log
-rw------- 1 root root 0 Dec 27 13:57 openvpn-status.log
user@myserver:/etc/openvpn$ sudo lsof | grep openvpn-status
openvpn 15116 nobody 5w REG 8,1 743 258326 /etc/openvpn/openvpn-status.log (deleted)
openvpn 24313 nobody 4w REG 8,1 17894 287910 /etc/openvpn/openvpn-status2.log
I stopped both of my openvpn services and killed the stuck PID
user@myserver:/etc/openvpn$ sudo systemctl stop openvpn
user@myserver:/etc/openvpn$ sudo lsof | grep openvpn-status
openvpn 15116 nobody 5w REG 8,1 743 258326 /etc/openvpn/openvpn-status.log (deleted)
user@myserver:/etc/openvpn$ ps aux | grep 15116
nobody 15116 0.0 0.4 45332 2732 ? Ss Sep12 46:38 /usr/sbin/openvpn --writepid /run/openvpn/server.pid --daemon ovpn-server --cd /etc/openvpn --config /etc/openvpn/server.conf
user@myserver:/etc/openvpn$ sudo kill 15116
The result was no more stuck openvpn PID accessing the file
user@myserver:/etc/openvpn$ sudo lsof | grep openvpn-status
user@myserver:/etc/openvpn$ ps aux | grep 15116
user@myserver:/etc/openvpn$ sudo systemctl start openvpn
user@myserver:/etc/openvpn$ sudo lsof | grep openvpn-status
openvpn 27793 nobody 4w REG 8,1 17896 287910 /etc/openvpn/openvpn-status2.log
openvpn 27795 nobody 4w REG 8,1 663 341483 /etc/openvpn/openvpn-status.log
user@myserver:/etc/openvpn$
All is good now
user@myserver:/etc/openvpn$ ll openvpn-status.log
-rw------- 1 root root 663 Dec 27 15:21 openvpn-status.log
user@myserver:/etc/openvpn$
