Found a nice apartment to rent, and got rejected by the owner in the middle of the application

I found very nice apartment.
Contacted the agent, prepared the documents for application, and finally made an appointment to view the room.

When the agent is in the middle of opening the door, a woman came to us and asked　どちら様ですか
I am shocked by this question and thought it's some annoying おばあさん neighbors.
So my agent introduced me and explained that we had an appointment.

And it turns out it's the owner of the property.
Somehow she isn't aware that I am going to rent the room.

Then my agent made a few phone calls trying to sort things out.
In the end my agent has to return the key to the owner coz the owner is not willing to lend the apartment to a foreigner.

My first room searching in Japan and it's the strangest experience I have ever encountered.

After going back, I can even see company B, C, D, E listing the same property I am interested in.
Is it normal to have so many companies listing the same apartment and the owner is not aware of it?