For what it's worth, this is the switch PoE status page (at the time I took this, 3 of the R710's were connected to ports g2 - g4), with port g1 - g8 all theoretically able to deliver full PoE+ 802.3at power, and all connected APs are correctly identified as Class 4.
And here is an example LLDP port config for g2, showing optional TLVs transmission, which includes Extended Power via MDI.
Yet the R710s still stubbornly stay in 802.3af PoE Power Consumption Mode.
how many other ports do you have connected with PoE devices on this switch? Have you tried changing the priority to high on one of the R710 ports and rebooting the switch? It is applying class 4 so it looks like the switch is recognising that it is a PoE+ device.
There's only about 10 other PoE devices connected at the moment - mostly low power. The switch has a nominal power budget of 384W, but is currently only showing 60W consumption, so I assume nothing is getting throttled by the switch itself. I previously put them all up to high priority and rebooted everything, but it unfortunately made no difference.
Ok, as the switch seems to be detecting class 4 via LLDP i am leaning towards the AP choosing to go into af mode for some reason but still requesting .at power (based on lldp power from OP and bug ZF-14489 from Max's post). Do you have any other 802.3at complaint switches you could test with? Will do some more digging on R710 & PoE+