Offset/shift frost skirt to floor slab

Hello everyone, we need your expert advice. During the construction of our single-family house, it was found that the frost skirt under the slab including insulation was not built flush. Our frost skirt has an offset of about 17 cm compared to the slab. Thus, all water can flow into the frost skirt and in case of frost we will eventually have a problem. The planned target – namely a flush connection between slab and frost skirt – can no longer be achieved because the house is almost finished. After many discussions with construction experts and the construction company, the construction company has now offered to somewhat align everything with a bitumen fillet with [Noppenbahn]. Our expert says that this could be a solution, but nothing for eternity and that we will have to dig from time to time to check if everything is still aligned.
Do you have experience with this issue and is there another way – apart from demolition and rebuilding – to sustainably get this problem under control?

Thanks and best regards