8600 SMLT-IST issue

[aclaybaugh]

We have had an issue with the IST on a pair of 8600s a few times in the last 6 months. We just upgraded to 4.1.4.0 and just had the issue this morning. The two 8600s having the issue have two ports each defined to the IST. The SMLTs are going to three more pairs of 8600s as well as some 5520 stacks.

STP is disabled on all ports in the IST and SMLTs. When this happens the IST goes down taking down all the SMLTs. About 1-2 minutes later the IST and SMLTs all come back up on their own without any intervention by us.

Any ideas? Below are the syslog messages from one of the 8600s. There are no other messages before this happens.

MLT INFO smltIstSessionDown
SNMP INFO Smlt Ist Link Down trap received
SNMP INFO Smlt Link Down Trap(SmltId=1)
MLT INFO All the SMLTs are down
MLT INFO smltIstSessionUp
MLT INFO SMLT 1 UP
MLT INFO SMLT 3 UP
MLT INFO SMLT 4 UP
MLT INFO SMLT 5 UP
SNMP INFO Smlt Link Down Trap(SmltId=3)
MLT INFO SMLT 6 UP
MLT INFO SMLT 7 UP
MLT INFO SMLT 8 UP
MLT INFO SMLT 10 UP
MLT INFO SMLT 11 UP
SNMP INFO Smlt Link Down Trap(SmltId=4)
SNMP INFO Smlt Link Down Trap(SmltId=5)
SNMP INFO Smlt Link Down Trap(SmltId=6)
SNMP INFO Smlt Link Down Trap(SmltId=7)
SNMP INFO Smlt Link Down Trap(SmltId=8)
SNMP INFO Smlt Link Down Trap(SmltId=10)
SNMP INFO Smlt Link Down Trap(SmltId=11)
SNMP INFO Smlt Ist Link Up trap received
SNMP INFO Smlt Link Up Trap(SmltId=1)
SNMP INFO Smlt Link Up Trap(SmltId=3)
SNMP INFO Smlt Link Up Trap(SmltId=4)
SNMP INFO Smlt Link Up Trap(SmltId=5)
SNMP INFO Smlt Link Up Trap(SmltId=6)
SNMP INFO Smlt Link Up Trap(SmltId=7)
SNMP INFO Smlt Link Up Trap(SmltId=8)
SNMP INFO Smlt Link Up Trap(SmltId=10)
SNMP INFO Smlt Link Up Trap(SmltId=11)