Flat roof vapor barrier not correct like this, right???

Good day,

So far we have had problems with every single craftsman...
Now the roofer has started.
First, of course, the rafters were installed... a few of them are too long so that they press into the insulation.
I'll just let that slide for now.... On the other hand, the roof boarding is already on...
Of course, they also forgot to remove the foil from the glued laminated beams...
So now I have to remove the foil with a box cutter.... Great..

Now to the actual problem..
As far as I know/understand... a vapor barrier must be installed on the roof boarding, and this MUST BE AIRTIGHT, or am I wrong?
Then the tapered insulation goes on that, and on top of that this paper is welded, right?

And now please tell me something about the vapor barrier... it has been installed catastrophically.
Or can it be left like that?

Please get an expert who can also tell you exactly how it needs to be done... no one here can surely manage that.