I haven't really played with iscsi. However, it is possible to have 2 or more paths to the same SCSI disk. I'm wondering if that is what is occurring here?
This
page has discussion about multiple paths with iscsi so may be of some help.
Another idea: It is possible that a drive that was say /dev/sdi on one boot becomes say /dev/sdp on the next. Did you do something to make the the sdd and sde names get created manually on each boot (e.g. with udev rules)? If so is it possible the sdf and sdg names were created by the boot while the sdd and sde were created by your rules?