Later, over cold coffee, I reread the last line of the release notes. The one the engineers always add as a joke:
End log.
Yeah. I’ll schedule it for next week.
I re-authenticated the session (fix #1). I ignored the humidity sensor (fix #2). I rewrote the valve script to use tty_s7_secure (fix #3). I clicked through six menus to find the bypass (fix #4). And finally, I saw the truth: the scrubber was frozen. scos 7.4.21 release notes