Hi @JulianWolf
That is the case for dev-mode only. It is not a new feature, and when your app gets published on the marketplace, it will start getting a single shared secret for all installs(including subsequent install) as it was before.
Coincidently, we actually were planning to provide unique shared secret per installs in close future. Here is the announcement that I’ve made just a moment ago which summarises this plan.
FYI, there is no additional actions required as long as your app works fine in dev-mode for multiple installs in different tenants.