Here is the story about this bug.
I'm running OSPF on OVPN.
The log showing a lot info.
The netmask mismatch.
It is very weird. Because the IP address was provide by OVPN server.
I go to check the both IP address on OVPN server and local router.
As you see, the local router has /24 netmask, but the server has /32 netmask.
This cause OSPF issue.
I also check L2TP and PPTP, they using same profile from OVPN.
The remote router and local router all are /32 netmask IP addresses.
Is it anyway to fix this?