On April 22, I filed a bug (FB9992639) with Apple's Feedback Assistant titled "Bluetooth re-enabled after every iOS and macOS update". I believe this issue started with iOS 14 and macOS 11, but in any case it definitely happens now with every iOS 15 and macOS 12 update, including today's iOS 15.6 and macOS 12.5 updates, on every device I own. (I think Apple stopped re-enabling Bluetooth for Big Sur security updates after Monterey was released.) I finally decided to file a bug with Apple after I upgraded from my old MacBook Pro running Big Sur to a new MacBook Pro running Monterey, because I was filing several Monterey bugs at the same time. Here are the steps to reproduce from my bug report:
Expected results: Bluetooth is still disabled.
Actual results: Bluetooth is enabled.
Note: There are two ways to disable bluetooth on iOS, one temporary and one permanent. The temporary way is with the Bluetooth button in Control Center, which disables Bluetooth until you restart your device or 5am in the morning, whichever comes first. In contrast, my bug report is about the "permanent" way, which involves switching off Bluetooth in the Settings app on iOS or System Preferences on macOS (now System Settings, sigh).
Today I got a response from Apple to my bug report:
Thank you for filing this feedback report. We reviewed your report and determined the behavior you experienced is currently functioning as intended.
You can close this feedback by clicking on the "Close Feedback" link. Thank you.
Needless to say… wow. And to be clear, the above quote was the entirety of Apple's response to my bug report. No explanation of why, just functioning as intended.
This is so incredibly user hostile. If you're wondering what's wrong with re-enabling Bluetooth — aside from the obvious: blatantly disregarding the user's preference — you can Google a list of security vulnerabilities in Apple's Bluetooth stack. I personally don't use Bluetooth for anything and don't ever want it enabled on my devices.