Hi Sejin,
What kind of instability are you experiencing? You write "AK Components are initialised" but that sounds to me like it's working properly?
Could you describe in more detail what the problem is? Do you get any error messages in the Profiler?
In my experience, we do have a very solid integration in Unity. Not only because of the team that is maintaining these scripts, but also because a lot of it is based on Unity's own mechanisms. Like when you play events on entering a trigger, the Wwise Unity Integration simply uses the OnTriggerEnter() main function in Unity.
Nevertheless, if you have problems with instability like events not playing consistently, it's always a good idea to hook up the profiler and study the capture log. It may be you need to adjust your Wwise Initialisation Settings, and if so, Wwise would tell you in the Profiler.
Let me know how it goes.