I have driven multiple EVs with this feature including trains. Regenerative breaking always has a delay, because the electrical fields need to build up before they can exert force on the motor first. I’d guess it takes about 1/3 to 1/2 of a second for the full force to be applied. Again, every train breaks regeneratively as well and no one ever said in my life, that they were getting sick on a train. This article may be clickbait, that’s all I’m saying.