Ethernet is showing my computer to be connected to wrong network?

Hello guys,

I was hoping someone could give me some insight into this slight issue I've been having with regards to my networking.

Here is my layout:

-My main Verizon router is located upstairs in my computer room. This router is wired to another Asus router for wireless coverage in the basement. This router is also wired to a series of switches.

The issue I'm having is that the devices which are wired to the Fios router via the switches are for some reason, being connected to the Asus network, instead of directly connecting to the original Fios router network.

This is causing some strange symptoms. I have already configured the Asus router to be in Access Point mode, but I don't understand how the devices upstairs are somehow being forced to go through the router in the basement.

My ideal setup is having only devices on each floor to be regulated by the respective router, or even better, have ALL DEVICES regulated only by the Fios router, and have the Asus router simply act as a wireless and wired access point. Any insight at all would be helpful. I apologize if my logic is flawed, I am not very experienced.

TL;DR: Main router is connected to secondary basement router and upstairs network switch. For some reason, devices connected to upstairs switch are showing up on downstairs secondary router.