ᐅ Should the slab be notched out, cut away, or left as is?

Hello,
Our garage builder made a mistake with the concrete slab. At an inward-opening door, the slab has no recess, meaning that from the outside, with the door closed, a part of the slab is visible. This is where the paved driveway is supposed to connect later.
The garage builder says it’s no problem; the team installing the driveway can just cut the paving stones thinner, and that will work.
I don’t have a quote for the driveway yet, so I wanted to ask if he’s right?
Or should they simply cut away that part of the slab and waterproof it again? Is that even possible? The garage is finished except for the screed; the doors and the garage door are already installed. The slab is reinforced with iron fibers and is 18cm (7 inches) thick, if that matters.

Thanks a lot for your help,
morgenstern