Assuming both reports (video and comment) are actually with 12.4, it could potentially reflect the neural networks are overfitting to cleaned training data and overeacting to unexpected real world differences, e.g., camera calibration or sensor quality. Something simple as a bug splat partially blocking the front cameras in just the "wrong" way could confuse neural networks especially as predictions in general are made more sharp.Unexpected things happen in the real world, and it's better for Tesla to fix the software now than after rolling it out to us.
12.4 neural networks can still be 5x-10x better in the expected conditions but also perform worse for unexpected situations.