It's hard to say... If these are like a PPPOE connection that is dynamic and changing in nature before your ike timeouts you might see this.
DONT DO THIS ON A CONCENTRATOR....!!!!!!!!!!
commands to flush ike / ipsec / etc...
NOTE: These will clear all
clear security ike security-associations
clear security ipsec security-associations
NOTE: These are by index
clear security ike security-associations index <Number>
clear security ipsec security-associations index <Number>
NOTE: DROPS HAMMER
restart ipsec-key-managment
NOTE: DROP HAMMER HAMMER
commit full