Is your base perhaps sealed again under the insulation boards? It is also important that the sealing extends beyond the terrain surface edge and does not end directly at the ground. Then make sure to talk to the craftsmen before carrying out the next trades (height and position of the washbasin and toilet, for example). The height of the shower head is also important. If you don't say anything, the craftsmen will do as they please. We also marked the position of the toilet paper holders and towel holders ourselves. It was also very important for us to check in every day during the tiling work. With large-format tiles, there are many possibilities for where to start, where to cut, and where the joints will be. It is best to discuss the possible joint transitions to different rooms and walls in detail as well.
Best regards
Sabine