Deep Dungeon Saving Issue

I just queued for deep dungeon with a friend as party leader, and we selected to have players added to our group, instead of a preformed group. When we finished with floor 10 I wasn't given the ability to save. When we tried to move on we were told we couldn't due to gear, so we repeated 1-10 and once again I wasn't able to save.

When I checked the NPC later both of my save slots had been filled. This seems like a big issue; if the purpose of the two save slots is to allow for different job choices or different party formation choices, and it autofills/overwrites them in the scenario I was just a part of, what is the point? It seems like very little testing was done here.

you save the floor 10 by going though the glowing blue exit it saves your progress when you enter the mid way room between floor 10 and 11. if you leave via duty finder it dose not save your progress

Right, progress was saved, that is not the issue. The issue is that each time I went through a different save file was selected each time, there was no decision making.