Recently, after extending a wireless network on a setup with one Extreme and one Express (both AirPort base stations), I've been experiencing issues regarding which base station extends which on a certain iMac. Note that when it actually works, it works great.
I have the AirPort Extreme connected to a modem via Ethernet, but an AirPort Express that is generally closer to all of my devices extends this network (we can't change where our modem is without our ISP having to send someone over to re-wire practically everything). The screenshot below explains everything.
I cannot use Internet on this particular Mac when it is acting this way.
Any suggestions or explanations as to why AirPort Utility would show it in this strangely ordered diagram?