I am hallucinating the radical altitude changes.
I would not know about that. But this
The problem is it [the pressure update] doesn't happen in FG over 30 miles. It happens in one update.
is a very specific claim that the full pressure change between old station and new station happens in less than 1/120 of a second (that is one FDM update cycle).
It's not a claim that the change can be 'rapid' or 'radical' - not even a claim that there can in principle be jumps - but a claim that the new pressure is instantaneously applied.
Note that this scenario is very different from e.g. a rapid change across 5 seconds as claimed by V12 - 5 seconds are 600 FDM iterations, instantaneous is one (!) FDM iteration - so in the first case the code has a few hundred times less stress to cope with any change.
1/120 of a second is far too small to estimate by eye-balling, so you could not possibly know whether that actually happens without a log file obtained at high sampling rate.
If you just want to talk, you can be as imprecise as you like - but if you want to debug software or report issues, you need to learn to be precise about what the issues actually are - you can't simply magically turn an eye-balled observation into something much more precise.