What's causing this drop?
Probably a correction that was going to happen anytime.
There is no avoiding the fact that the price was obviously a bit too bubbly, and an adjustment downwards was needed before there is a price rise again. After the ETF decision there was a short squeeze which left shorters stunned.
But then after everyone's attention shifted out of the ETF it went to the hard fork.
And that's bad news for bitcoin, as there is a ton of infighting going on.