Ability to get user/customer info from Vipps API

We've been running this on a client for about a week now, and it's been working great for us.

We have an issue where about 4-5% of orders have no address information, which we don't know the cause of, but I'm leaning towards this just being a problem with off-site payment methods, rather than a problem with this particular implementation.

Scratch what I said above. We're now seeing that this event isn't invoked for many of our of orders. Looking at the code I'm thinking that this is because these are orders where the user isn't returning to the website and thus onReturn() is not called, and therefore not this event either?

I'm thinking that this event needs to be invoked from onNotify() as well? But I feel like I've overheard that you're not supposed to save the order in onNotify()? And we're currently using this event to fetch address information from Vipps and save to the billing profile.

I need some insight from someone more knowledgeable than me on this :)