Why do I see a vehicle in the My BMW App but not in the My BMW portal?

BMW vehicles with Operating System 8 (software version 07/2022 or newer) can be connected to the BMW IDs of a primary user and up to six secondary users. The primary user is the person who first added the vehicle to their BMW ID, e.g. by logging in to the vehicle. Secondary users have limited rights and can see the vehicle in the garage of the My BMW App, but not in the My BMW portal.