We have a Cisco ASA 5545 with software version - 9.8(4)41
We are having lots of strange issues going on with NAT, whenever we add objects, or amend NAT rules, it deletes random rules, changes source and dest ranges and randomly reorders them, this is causing us lots of issues.
Has anyone seen this?
What is the recommended stable version we should upgrade to?
Which software do you use to manage NAT and ACL rules? Is it CSM, ASDM or CLI? With CLI, what you describe should never happen. With CSM I faced with NAT reordering once, but this was very corner case too, caused by "inactive" NAT rules. Blind ASA software upgrade won't probably help you until you get to the root cause of the issue.
I would advise to go for latest 9.12 Interim release (as of this moment that would be 9.12.4-54). Although highest supported version would be 9.14 for this platform, it will have shorter lifetime than 9.12.