Can't change security policy or disable SIP with macOS 15 Sequoia

from blog The Desolation of Blog, | ↗ original
My M1 Mac mini, which I use for software testing, has five APFS boot volumes, one each for macOS 15 Sequoia, 14 Sonoma, 13 Ventura, 12 Monterey, and 11 Big Sur. Today I learned that I can no longer change the startup security policy or disable System Integrity Protection (SIP) on any of the boot volumes. (I actually didn't bother to test macOS...