It’s a known thing with the AI and unfortunately the way it is. The AI isn’t limited to what it should know, or shouldn’t see like missiles coming from underneath them. Are you seeing better results using the same tactics against human players? I think that the AI’s tactics using countermeasures are just one piece of the puzzle.
The behavior that I’m seeing would suggest multiple issues and not just one related to countermeasures. I’ve fired missiles from 10 miles away at targets coming in hot being tracked in tws and the missile just flys right by them almost like it didn’t track. I’ve also seen missiles fly up to 80,000 for some reason like they are going to space.