Hmmm… this seems to be where the bug diverges for us. For me, the Sampler Tracks won’t show up even when I add a new track. I’ve tried adding audio tracks, instrument tracks, and group tracks.
At 0:24, I add an instrument track loaded with Serum to the project. Oddly enough, it actually REPLACES the sampler track that was already listed; it doesn’t refresh and show the sampler tracks that are in the project… so the bug must be a little different for us, or it is not consistent with this rule. I’m on windows 10 running version 10.0.15