This is probably where my expertise ends.... not that I had any with these devices...
The only other point worth clarifying may be when you added them to your hub / mesh? I'm going to take a wild guess and suggest they may assume a neighbour status for a short period when initially paired.... Could be wrong...
Hopefully others can chime in and solve this riddle...
There are also other Zigbee devices that do not report correctly whether the routing function is enabled or disabled, others do not report correctly the power source (battery or mains), etc.. Usually, this does not create a problem in the Zigbee mesh (except the wrong presentation in the graph app).
Yes, the routing table shows what is in the device descriptors, as reported by the device itself. These devices are not routers, so they do not advertise/broadcast routing functionalities in the mesh. If this was a problem, it should be a problem for any Zigbee hub, not just HE.
Sorry, to add to my report that mine show up as repeaters (blue), yes it seems to just be reporting as such not attempting to or actual repeat anything.
These are still on my C4, I can move one to my C8 and see if that changes anything having been newly added.
To be frank, that routeandchild endpoint is not reliable for providing a complete or accurate picture of what's going on with your zigbee mesh. And since that graph tool is just an alternate presentation of that info, it too should not be trusted for anything.
I contend folks are better off just pretending neither of those tools exist - I have yet to see an example of any good coming from it.