The "Bitcoin Unlimited" node count experienced a very sharp ~65% drop around 7:30 PM UTC as a remote-crash vulnerability was made public on Twitter. The node count, as reported by coin.dance, fell to 259 from a previous measurement of 764 moments earlier.

The actual vulnerability is a result of the ineptitude of the "Bitcoin Unlimited" developers to incorrectly implement the usual "monkey see, monkey do" approach to software, by messing up the copy-pasting of power-rangerolade.

Peter Todd's straight Twitter disclosure was made in a context of heightened tensions among the two main flavors of idiocy, namely the SegWit peddlers and the Roger Verified "Bitcoin Unlimited" followers.