Sealing compound. Whether it is silicone or something else depends on the materials used. That should not be a huge problem. How nice it ultimately looks is debatable. But what is important to me is that the tightness is ensured.
Received a response from the manufacturer of the plaster strip (whether one can trust it now or not...): It is not visually okay, and such interruptions should be avoided, and if at all, only in the upper area. But the tightness is ensured by the adhesive strip on the underside, the lip is more for the appearance. (just in case someone should also notice that on their house) Best regards