Ok. Those were the clues I needed. Cipher was a wild goose chase, the warnings weren’t dealbreakers.
The status option was the culprit. I was confused by the option --status status in the .ovpn file, but the second ‘status’ is the name of the status file. The filename is obviously not fully qualified here, so where it lands and who owns it would be implementation dependent. That would explain why things might work fine in one OS and not another.
I started troubleshooting, but before getting too far I tried just commenting out the offending line. Apparently it’s not necessary, at least for my purpose, so problem solved enough for now.
Now to make sure house hasn’t burned down in my absense…