You are right. The point I was trying to make is that the triggering and processing is done in the external module and, although the signals are time-correlated in the scope screen, the 800X-HD doesn't get the full data. As such, it is not truly MSO, which shows in the triggering, for example.
It sure is useful, but not equivalent to the 2000 series Siglent scopes, the MSO5000, or the DHO900. Bugs notwithstanding anyway.