Comment 14 for bug 1824465

You need to start out with a 2.4 model and upgrade.
The initial model needs to be created with the old basic SKU type.
On the upgraded model, Juju will by default use the Standard SKU type, so you use the model config to switch it back to Basic. But in making API calls to Azure, Juju is missing places where the SKU type needs to be passed in, so there's a mismatch.