This may not be the sharp abrupt movement that has been happening, but it clearly happened on the clap, and was a designed action. IMHO, it was intended cause a defensive reaction, and that is a false start.
Unfortunately, we don’t really know if the clap/motion was called as the FST, or the tackle. But, if this clap/motion gets called a few more times and the coaches realize this will be called, maybe, just maybe, they’ll stop trying to use this to cheat. They’ll move on to something else, but maybe this will go away.