I think it’s totally reasonable to question if the reference amp is in need of service. There’s nothing to say an amp tech can’t make a mistake, a single component can’t get worn out or fail in a non obvious way, or that this particular amp was made with a bad part in the first place and missed QC; there are many possibilities. And if a particular Diezel is not an amp Cliff bonds with, he might not realize there’s a problem.
If so many people wrote that the real thing is different than the model, and Cliff writes that the model is dead on, it’s totally reasonable to assume everyone has a different point of reference. And maybe it is the difference between the versions of the real world amp, as some have guessed.
I also think another problem is a lack of recordings en mass demonstrating what people are perceiving; although some have had the chance to post this type of recording, more of them would help immensely. Not everyone has the time to do this, but for those who do, it would be invaluable to record the real amp back to back with the model, with the sound dialed in by ear to be as close as possible with BMT/Presence, and Depth, into the same IR. Perhaps that would make plain to Cliff that there is a definite discrepancy, that even if the model perfectly mimics the source amp, maybe that source amp is the real problem.
And of course, it could just be an error with the model. Perceiving a model to be dead on is based on context. Maybe for the owners of the real deal not only to provide audio examples of the discrepancy would help, but also to upload the dry input recording of the guitar signal, so that Cliff could run those into his real amp and see if, in the context of those guitars, it just sounds broken. From my experience, every guitar and every player is going to exploit a different set of sounds from the same amp; the source is everything, and maybe there are contexts that demonstrate problems where particular scientific measurements do not.
This is a beta, so the whole point is find problems. We ought all encourage that rather than blindly rallying behind the flag just because we love Fractal. When we all try to figure out where there’s a potential issue, everyone using this unit benefits. There’s no need for the act of posting that a problem exists to be controversial.