1. Its a router in fact, the reason I said I added an AP is because the second router just work like that (an AP or WAP in this case). They are connected with an ethernet cable in a LAN-to-LAN setup to make possible for devices in both "APs" to be LAN accessible from other side (so I can stream from PC to the TV connected to B for example).
2. I cant find any related option in the A router to disable such feature, so I may think of it not being present in this model. Particularly because as Ive said I can see the full DHCP procedure between a device connecting to A wirelessly and A itself with the sniffer located in my PC, but cant track this one procedure fully when Im connecting to B (as it goes to another LAN port), or when the problematic happens (because I guess due to the CAM failure its the same as connecting to B, as the Tablet physical port address is not refreshed in such table to change from Eth2 to Wlan).
A-model is a Hitron CDE-30364
B-model is a Conceptronic C54BRS