If this turns out to be correct, and that an update has indeed broken third party rapid charging, then that's a really serious indication of something that I've suspected for some time, which is that the software testing process within Tesla is not fit for purpose. That may sound harsh, but these are cars for which much of the software is super safety critical, more safety critical than many other cars, simply because just about everything on a Tesla is under software control.
Although we only get to see obviously visible failures, like this one (assuming this is true), we can sometimes speculate that other things may not be behaving wholly as expected due to probable software issues. What we cannot easily see are the problems that are not at all obvious most of the time, some of which may well be a serious accident waiting to happen if the wrong set of conditions happens to occur. If something as simple as properly testing the DC charging communication protocol can be omitted from pre-release software testing, then what else doesn't get properly tested?
This is not the first time that the charging system has suffered from major software bugs, either. The Model 3 was sold with what amounted to a fake compliance certificate for around 18 months, as AC charging did not comply with IEC 61851, even though Tesla claimed it did. That got silently fixed around June last year, but for the first 8 months I owned the Model 3 the car was non-compliant, in that charge point controlled timed charging did not work, neither did charge resumption following a power outage (even though the manual wrongly stated it did). We've also seen charging bugs appear more than once that impact the charge current setting, causing issues like the charge current being halved a few minutes after charging commences. Perhaps we can hope that it's just the team developing and testing the charging-related code that have issues with testing, but it doesn't exactly inspire confidence.
For balance, I'm every bit as concerned about the VW ID.3, and it's major software problems. Compared to the approach used in aviation for software testing and qualification I have a strong suspicion that the automotive industry is lagging way behind. "Move fast and break things" may work OK when the most serious consequence of an issue is something like Facebook not working for a few minutes, but death can be just a couple of seconds away if something goes seriously awry in a car. Arguably, cars need a more rigorous approach to software testing and qualification than aircraft, as most of the time in an aircraft there's not anything close by moving at a high closing speed, so there's often more time to sort glitches out.
