Good Morning John.
I have had my Tucson Phev for about 4 weeks and have had no issues with the SatNav. Although I have not set it up with landmarks/POI . When I go out later today I will see what happens.
There is a Hyundai Tucson Forum UK you can go on to ask questions, someone may have come across the same problem.
Hope you are enjoying the car. I’m finding mine to be a good comfy car to drive. Any questions just ask.
Take Care.