Most people who've worked in Software Development would know that what most likely happened is that the team HAD to get the software update out before Christmas so Elon could tweet about the light show (deadlines are usually something more arbitrary and mundane that you only find out about after the fact, e.g. CEO's wife's birthday).
The development team then cut some corners in testing UI changes in actual cars, they probably got some additional must have features snuck in, and then pulled late nights just to get it live before Christmas (notice how the influencers got the release about the same time as the rest of the fleet). Corners were cut with the unspoken understanding that they could fix the bugs after the holidays.
Par for the course for most enterprise software projects, but far from what's expected from a company that brags it's a software company. Their UX team is probably still taking a long hard look at themselves in the mirror every morning.