I was just like you as well, but now get a decent amount of ping ponging. Occurs in a very subtle way without cars around in a very regular back and forth beat. With big trucks and especially at night NOA becomes unusable as the car makes drastic ping pongs in a delayed fashion after cars pass by.
This all started with a couple updates prior (although I’ve been stuck in the past since I have MCU1). Now I’m a believer in the ping ponging and get to eat my shoe, before I thought people were being overly sensitive...
It hasn't been
good since the first 9.0 release. That was when it really took a nosedive stability-wise. On the other hand, other aspects of lane keeping (e.g. ramps) got a lot better in that release. Basically, when it is going slow enough for the autopilot hardware to keep up, it does better in later releases, but at highway speeds, it is constantly oversteering and correcting at nearly every single curve.
It took another turn for the worse somewhere in the neighborhood of 2019.32, I think, or maybe a little before, and it feels like 2019.36 was even worse than that. I was only on 2019.40 for part of a day, and it seemed fine, but I only used it on streets with minimal curvature, so I can't say for sure. 2020.4.1 feels about the same as 2019.36 — possibly slightly worse, and possibly not slowing down enough on some tight curves, but those things could be entirely my imagination. It isn't clearly worse, but it definitely isn't better.
+1 to the ping-pong issue. HW2.5 here, though it seems like HW3 isn't affected? It appears the lane centering control system is underdamped as the car not only often takes a up to 5 seconds of ping ponging to "find" the center of the lane but also overshoots and crosses lane lines when making significant adjustments (merges, exits, lane width changes, etc.) This has certainly made for some "exciting" moments on autopilot.
That's consistent with my experience as well, though I've never seen it cross lane lines except on roads with really tight turns, where it ought to be slowing down way more than it does (e.g. Hecker Pass). I have seen it be on top of the lane lines on CA-17 once in a while, though, which is
almost as bad. This usually occurs when the thing randomly freaks out and starts oscillating out of control, a problem that can only be fixed by taking manual control, waiting five seconds, and kicking AP back in. I've only seen that a few times.
I wonder if the extent to which it misbehaves is dependent not only upon which car model and AP HW version is involved, but also on which steering rack version that particular car has. Failing to apply the right damping for a given configuration could explain why it seems to get better for some in the same releases where it gets worse for others.