Hi @mwlarsen, and welcome to the community!
What you are describing does seem like a known issue with our now rather old installer. The good news is that we now have a published recipe to create a new installer in the context of our rebase onto openSUSE. This will provide you with much much newer kernel and btrfs-version with a ton of improvements when compared to our previous installer. See the post below by @phillxnet for instructions and further explanations:
Sorry I was unfortunately not able to directly solve your problem, but I hope it answered your question nonetheless. Don’t hesitate to let us know if there is any particular customization you were trying to make with the old installer, and we might be able to do so post-install…
Hope this helps,