aaahhh, Even an analog tube amp can alias given the right circumstances so I would assume with the accurate models they'd do the same thing if you duplicated the same circumstances.
No it can't. Aliasing is solely something that happens in sampled-data systems (what we call "digital"). A good example of aliasing is the old wagon wheel spinning backwards at the movie theater. This is because a film is actually a sampled-data system. A tube amp is not a sampled-data system.
Our products do not alias. I would recommend trying a different monitor first. If you still have problems contact support. You really need to find a way to record this as support will ask for a recording.