This Has Me Worried. Broken BLK Brass
I fast forwarded to the middle of the video where you were annealing. The one case I saw was really over heated. The color change was halfway down the case.
I've never seen anyone use a shell holder. Use a deep socket that the case has a slip fit it. It acts a heat sink. You can flick the cases out of the socket easily. I dropped them into a bucket of water but it's not necessary. It was so I could handle them immediately.
Your torch doesn't have a pencil tip. You want a small defined tip that you can place at the neck/shoulder junction. A broader tip is going to spread heat all over the place.