OK I guess not 
Here’s my working nginx configuration making openhab available at https://yourdomain/openhab-tesla via VouchProxy, while retaining BasicAuth at https://yourdomain/openhab. This way I can use it in my car, and still keep the ios/android apps working.
If anyone improves upon it or has an easier way, it would be great to know, especially if something in openhab3 obviates this.
vouch-openhab.txt (6.8 KB)