ZFS Troubleshooting Steps for Storage: Request Queue Overflow

Ran into some issues going from FreeBSD 9 Stable to 10 (FreeNAS 9.10) with a Qlogic's 2532. Looks like the HBA is work fine but the LUN disappeared from the ESX's system after the upgrade. After trying to rescanned the data store got a error message at the console of the NAS.
isp_target_put_entry: Request Queue Overflow
Cannot break out of this above error message from the console and a hard reboot is required to get past this issue.

Looking for some guidance on troubleshooting iSCSI and HBAs with ESX? So far I have the following....

After the update and reboot the storage can be seen by ESX and as soon as the storage is scanned or I try to remount the data-store, I get "isp_target_put_entry: Request Queue Overflow" and the storage disappears from the ESX systems. But things still look somewhat normal on the storage side.
[root@nas2 /]# ctladm port -l

Port Online Frontend Name     pp vp

0    YES    tpc      tpc      0  0
1    NO     camsim   camsim   0  0  naa.5000000fcdd40702
2    YES    ioctl    ioctl    0  0
3    YES    camtgt   isp0     0  0  naa.21000024ff5ebccc
4    YES    camtgt   isp1     0  0  naa.21000024ff5ebccd
5    YES    iscsi    iscsi    257 1  iqn.2011-03.org.example.istgt:esx,t,0x0101

[root@nas2 /]# ctladm devlist

LUN Backend       Size (Blocks)   BS Serial Number    Device ID

  0 block            6442450944  512 002590ebc8ec001  iSCSI Disk      002590ebc8ec001
What would be the next best commands to try to figure out the cause of the error message:
isp_target_put_entry: Request Queue Overflow
Thanks and Thoughts?