Apparently infected have received a new "stepover" animation with which they can step over narrow obstacles, to e.g. ge into train carriages from a platform. However, the animation is not fully aligned with the namesh, leading to them sometimes falling through the floor and walking inside or below it. See this short video somebody posted on twitter:

https://twitter.com/BardThorium/status/1507681554759401473?s=20&t=yPlkfAQccAEnUNgSqTyVHA