The dev team posted this as known bugs, see here.
The way I’ve fixed the unknown plug and losing samples (it’s the same issue) is basically getting the new FX and synth engines via the Configurator (oh, and the RedMount sample pack) and once that’s loaded, head to Disk mode to put back the samples in their slots (it helps to have a previous backup of course).
The app saying “unknown plug” is just referring to the fact that you’re in one of the user samples that got lost. Just use Track+1-0 to get to a factory sample and you’re good.
Hope this helps!