Connection of foil on the first upper floor

Hello everyone,
Our house construction company glued the foil at the ceiling to the wall. The connection points do not seem very neat to us, so that the intended insulation might not be fully achieved.
It is the first upper floor and above it come plasterboard panels. Above that is the attic and then the hipped roof.
We would very much appreciate your opinion.

Thanks in advance.

Come by again and make improvements.

...so our fear is confirmed?

Yes, it doesn't really seem to be watertight. And it has to be watertight