I tend to agree with @FLDave that the problem was with precision landing rather than RTH. But having it occur at 50' AGL is odd. Isn't that beyond the typical range of the VPS system?
I've never read about nor heard that error message mentioned...
You might want to run through the Pilot Institute's free online "Deep Dive" course on the Air 3S. It's a very good way to get familiar with the drone and learn the features.
https://pilotinstitute.com/course/dji-air-3s-deep-dive/
The December 23 date is related to licensing of new DJI models. It has nothing to do with imports of Care Refresh. It's not retroactive; it's about new DJI models.
And given that no audit has been initiated, the limitation on licensing new DJI...