I think it's just a mere coincidence. Whenever there are huge transactions like this, people from everywhere are freaking out and that's the cause of the dump.
Everyone starts to sell and thinking that there will be a huge dump so they're doing it earlier before that transfer puts on sell order.
nah, because nobody is watching the blockchain ever to see these types of transactions so they don't even notice these types of movement. the only case when it comes to people's attention is when someone like OP finds a completely random big transaction and posts it on social media like this forum! and still that won't do anything to the price because it is not the first time something like this comes out.