"Record high" in an established business like Twitter isn't quite the same thing as a traffic spike in the growth phase of a startup (i.e. Twitter in 2011).
Record engagement these days is most likely measured in single digit percentage points over average engagement (at most maybe 10-20%), where when you're early and your traffic is spiking, it can be an order of magnitude more traffic than what you're used to seeing. The absolute numbers are larger yes, but from the perspective of "what can my infrastructure / architecture handle", relative changes are far more relevant.
Record engagement these days is most likely measured in single digit percentage points over average engagement (at most maybe 10-20%), where when you're early and your traffic is spiking, it can be an order of magnitude more traffic than what you're used to seeing. The absolute numbers are larger yes, but from the perspective of "what can my infrastructure / architecture handle", relative changes are far more relevant.