The landscaper said they would remove the rearmost stone in front of the door threshold and put in a drainage layer or something similar there? We have only briefly discussed it so far because he said I should first declare it as a defect.
Exactly! The "funnel" needs to be mitigated (heavy rain or so) and a small drainage layer (soakaway) is the quickest and most cost-effective option. And just by the way, if something doesn't work, it is a defect, as in this case. And that without emotion