400 miles is at least 5 hours of driving, which is a bit long for not even having a pee break. Since you're driving a BEV, it's also above the maximum range of your car, so you had to have stopped at some point, which suggests that there are details in your claim that are already missing because (you feel) those details don't matter to the essential truth of your statement.

I believe that you believe you made a 400-mile drive with full self-driving without any issues. But I also believe that belief can be made in good faith even if there were issues during that drive--either the things that did come up you don't mentally classify as issues, or you've just failed to commit what did happen to memory.

That's not a knock on you, by the way; recently, I've been struck in a number of instances the times where I have physical proof something happened yet I have absolutely no memory whatsoever of it happening while feeling that I would have had to have that memory. Human memory is notoriously finicky and fallible.