last friday i updated our zonedirector 1200 to 9.12.2.0.204 patch.
the notes gives an information about some fixes on poe , here the post:
"Resolved an R710 PoE issue that occurred when the AP was connected to a switch that only
supported 802.3af PoE mode. [ER-3225, SCG-47346]"
well, now after this patch we have poe issues!
before this patch running zd1200_9.12.2.0.101.ap_9.12.2.0.101 there was never any poe issue in our setup.
i started to test around why this happens after the patch update.
what i can 100% confirm is, that:
A) since good friday ( everybody was on holiday i could update the network) i see random restarts on r710 (all r600 running fine)

this problem happens only if the switch configuration PoE LLDP-MED is enabled!
(on a HP switch 2530-24G-PoE+)
so my solution for now, i will backport to zd1200_9.12.2.0.101.ap_9.12.2.0.101 tonight!