ASA is receiving the ICMP reply messages from x.x.x.x on OUTSIDE interface.
By default ASA allows only those ICMP response messages whose request was allowed ASA in the first place, in simpler terms ASA will allow only those ICMP response for whom session already exist on ASA.
So, ASA is dropping ICMP response messages on OUTSIDE interface.
You need to check whether the source IP x.x.x.x is same everytime or is it changing every time or do you see a pattern in the source IP of those ICMP messages.
If that x.x.x.x is a known IP then you need to check why it is generating ICMP response so frequently.
The behaviour which we are observing is expected behaviour.
Please provide the sanitised SNMP configuration, so that we can check whether it is possible to supress such traps or not.
