[General Maximus]

Without going into an depth explanation of how routing works I will summarise and say that it is more than likely that the shub was able to see the macs on the switch side when the devices were directly connected to it and now that are going through another switch/middleman the shub can now only see the tplink switch and not what is behind it.
That being said, my Linksys router see everything behind all 4 of my switches but I don't know whether that is specifically down to my router or a combination of the router's ability to do so and the fact that all my switches are Linksys as well.