When I scale the screen and move the bottom part it works fine, but when I try to move the top part upwards, this ends up happening on the top part.
I thought it was necessary to merge some vertices again, but I tried and it's still ending up like that.
HI Gabriel ZZeon ,
What you basically are getting is this, where the connecting Edge is 'crossing over' the circle:

So what you can do is, for instance:
