You sent the log file and we saw specific errors and feel re-flashing would fix issues pointed out in previous reply. If you wish not to assist then let's move on. Any errors, Event IDs or try version 2.02. If you are saying only the Snapshot is corrupted during active states of the Snapshot maybe their is heavy IO or not enough memory for the systems. Have you checked the performance values? For iSCSI Ent. use https://x.x.x.x/check_sys/127.0.0.1.html and review the loads for mem during the Snapshot. Sometimes running out of memory can cause this and with the 14 clients doing heavy I/O could cause this (now the execute_task_management(1236) starts to tell more). Then maybe increasing the iSCSI Deamon settings, RAM, larger bond....
You cannot use the iSCSI-R3 Enterprise USB with the iSCSI Enterprise IDE existing volumes, they are different volume managers - you have to backup and then restore.