I have a 2019 London Aire and it is most definitely a problem. The floor is sagging on some where the refrigerator sits and causing the tiles to crack, I know because National Indoor RV just reinforced the floor and replace 3 tiles in front of the Refer and pantry.
They remove the refrigerator and pantry walls, install reinforcement angle iron on the floor then line the inner walls of the pantry and outer wall between the refrigerator and dinette with structural plywood.
There is also a problem on some with the ceiling sagging. They go in and reinforce the header with a steel plate that runs the length of the header from the bedroom wall to the front slide wall. They notch out the header and install a steel plate, again it was done to mine.
Here are some pics of the repairs, unfortunately I did not get a pic of the plate before they started to reinstall the header trim. This all was done last week on my 2019 London Aire and National Indoor RV did a great job.
I will say I would not let this deter you from buying a newer model with the tiled slide. It is very fixable and who knows why, not every one does it.
2019 London Aire
4543 SL605 FCCC