Whatever you decide to tell Stark is up to you, but I second the suggestion of keeping it polite and diplomatic. Also remember that the person you are talking to probably isn't personally responsible for your issues, so it's also a matter of respect. You do sound like a polite person, but sometimes in these situations we -including me- tend to drop some F-bombs and end up being offensive when we just wanted to be defensive.
That said, technically I've noticed that the inverter was diagnosed to be manlunctioning after a battery replacement, so I tend to suppose that the new battery has caused this issue. A possible explanation could IMHO be that this new battery either delivers power in an erratic way or that it has damaged the inverter, for example maybe the precharge circuit is faulty and has delivered too much current to the inverter, damaging the DC link capacitor or the inverter itself.
Here is an explanation of what I'm talking about, if it's needed:
However, it's just a guess that is as good as yours since I don't have first hand experience, I just have developed an interest for this stuff.
That said, technically I've noticed that the inverter was diagnosed to be manlunctioning after a battery replacement, so I tend to suppose that the new battery has caused this issue. A possible explanation could IMHO be that this new battery either delivers power in an erratic way or that it has damaged the inverter, for example maybe the precharge circuit is faulty and has delivered too much current to the inverter, damaging the DC link capacitor or the inverter itself.
Here is an explanation of what I'm talking about, if it's needed: