Maybe, maybe not. Marble tends to dry slower than ceramic (which really does not adsorb water). How was the shower constrcuted? Was there a flood test? Could be water sitting under the tile as well if the pan were not pitched properly.

There is no way for us to halp without some clue as to the install of this shower. Waterproofing in a huge issue and not done right can create hell down the road. I can't even see how the tile was layed and the sideways pics are just plain bad.

Obtain a marble or ball bearing and watch how it rolls on the floor

It was sloped right when installed,house settled afterwards and caused slope to change. Not installers fault.

@klem1 How can say the "house settled afterwards" when OP wrote it's been only around 24 hours since the plumber tested the shower and it's never even been used by OP? Please do explain.

It's hard 1960 but people come here for answers and I've learned to furnish them without wasting time with evidence and such. It's just a given that tile layers doing that pretty of work don't make mistakes so it was level when he finished and by a stroke of bad luck,the house moved. Time was when I couldn't tell if the floor in picture was level or not but you know what they say practice does.

Klem is into some good wine !

It may be that the hazy tile makes the regular tile look like it's wet when it really isn't. The same thing happened to my ceramic tile shower floor when it was installed. After showering, the hazy tile would look like it had dried faster than the rest, but in reality the entire floor was dry. The contractor scrubbed the floor with something that removed most of the haze. Unfortunately I don't know what he used and we no longer are in contact with him.

Unless the installer admits to poor installation and re-does the job,let's hope the house moves back the other direction causing floor to be right again. Watching pictures on the wall is a good way of keeping track of what's happening if anything happens and when it's happening.