without setting regdomain, I had the problem where I was not able to turn on AP and STA at the same time: maybe because of chan 13?
probably the ping problem is something related to the Vodafone station that I was trying to extend. With a Raspberry PI with raspbian I had the same problem. Today I tried in an other environment, replicating wifi from an ORBI netgear, and everything was working right.
So as of now these problems are solved, but trying to solve the problems, I found that with the vodafone station, even if the router is connected to the network wifi, block the lede repeater in a strange way: I cannot ping or find the lede repeater from an other client directly connected to the vodafone station, but if I connect a client to the repeater I can browse web (with ridicolous speed, like 3-5 mbit instead of 60).
That channel has many restrictions, so yes, probably was channel related.
About the ping issue, maybe igmpproxy are failing or even it could be ap isolation problem too or some iptables/firewall rule.
About the slowlyness it could be just limitation of the hw... you really mean mbit? or mbyte? have you tried to put the repeater just a about 3 to 5 meters on the same room with antennas vertical... if you put very far, with walls, signal will degrade, and if you put very close signal will saturate and get noise, and if you put antennaes misaligned you may have unwanted signal bouncing around.
Recap of all the tests: The problem is indeed router (vodafone station) related.
3 days ago I tried with some GL.INET AR300M: when the configuration was like repeater not bridged, everything was ok: as soon as I put the repeater in bridge mode with relayd igmproxy etc I experienced the same behaviour of the 1043ND... doing reset of the repeater and reconfiguring it as router did not solve network issues reported above, but using a second GL-INET, or rebooting the vodafone station, made things comes back as normal.
I think the problem is related to some spoofing-block algo inside the vodafone station, because this is the only one router that caused me that troubles.
The speed reported above were in mbit. The tests were performed in the same room at 3m between vodafone station and the repeater, with repeater at 1 m above ground, and vodafone station at 2m. I'm a TLC engineer student, so I know what are the saturation / interference problems of the transmitters / receivers, but I wrote here because of the problem not present on the other devices (like smartphones and / or PCs), and the behaviour seemed to be pretty strange.