OAuth2 V1 vs V3 endpoint?

[mcolyer]

I've noticed that all of the documentation here refers to https://auth.tesla.com/oauth2/v3/authorize, however my account doesn't seem to be able to login via that URL while others are able to. When I inspect the login handshake on tesla.com for my account (which does work), it actually uses https://auth.tesla.com/oauth2/v1/authorize, has any one else seen this?

I only have solar panels and not other Tesla products and I'm wondering if that somehow affects it? My other thought is that maybe v3 is feature flagged for some users but not others? I've tried enabling and disabling MFA and it continues to use the v1 url.

I'd really like to be able to programmatically access my solar usage as I was able to do so before they changed how authentication worked.