macOS Sequoia beta external startup drive "out of date"

Getting alert "The version of macOS on this startup disk is out of date" for a Sequoia 15 beta

  • 8/8/24 installed and used macOS Sequoia on an external drive (on Apple Silicon)
  • Since then, updated main OS (also on external) to 14.6.1
  • No changes to external drive mounts or availability
  • Now unable to switch startup disk to macOS Sequoia

I see no other comments on the forums about this. Anyone else? Any tips? Would it be better on the internal drive?

It's a fair bit of time to install and configure; I'd hate to think any update bricks all that.

(Surprised/confused not to find forum tags for the beta systems, macOS, etc?)

As another data point, this is on an external drive with two volumes, and the other volume has 14.6.1 installed.

Seems like a serious issue?

macOS Sequoia beta external startup drive "out of date"
 
 
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