Have you checked the time of LUN trespass ? I haven't seen such a case of LUN trespass with a normal drive failure. Trespassing a LUN from clariion or doing it from celerra manager (restore SP A/B) will serve the same purpose.
Hello,      I have a few LUNs that mysteriously trespassed. According to the event log, the LUNs that trespassed were sharing the RAID group that housed the replaced disk. Is it normal for a LUN to trespass during a physical disk replacment? Also, this LUN belongs to a NAS gateway. Can I trespass the LUN back from the Naviphere, logged into the SP, or can I/should I trespass it back from Celerra Manager.   Thanks.  
LUN Trespass during physical disk replacement