I see a lot of topics talking about why bitcoin did this or that. Sometimes there are clear indicators as of why but many times it simply happens. Coincidence, trading bots and simple TA can affect the price and create a snowball effect easily.
Imagine 3 whales with 1000 btc each decide to sell bitcoin and by chance they do so at the same time. Of course the price will tank and people will wonder why, bots will follow and so on.
It's not all about the bots actually, there's more volume of real person trading compared to bots or limits set in the market or exchanges. But technically, if a person sees someone sells huge amount of bitcoin in the history, he/she will definitely follow to avoid being trapped in the market. Meaning to say that the popularity of an exchange where the selling transaction happen is also crucial.