Hi there,
If you went to System → Administration → Date & Time → NTP tab do the settings look similar to this?
More so, I will have to ask you to try & reboot the OpenVPN service if possible, but do that through the CLI/SSH by entering /etc/init.d/openvpn restart - let me know if it still takes a while to get back up, and if so, we’ll continue our conversation in a different communication channel so I could collect the logs from your device to send to our R&D.
Thank you,
M.