If mssfix wasn’t checked, before 162 (or so) the openvpn export just exported a settings file without a mssfix line. This was then up to the system to manage.
Since sometime mssfix 0 is added to the client file. This completely destroys OpenVPN network connectivity for Windows clients, but removing the line fixes everything again. mssfix 0 is also set in server.conf when one checks.
This seems like some kind of a mismatch between the client and server settings. I’m not OpenVPN-savvy enough to grok what’s happening here, so hoping for some help.