csrutil disable
Restart computer
In the terminal, type
sudo open /Applications/TextEdit.app /System/Library/LaunchDaemons/com.apple.ManagedClient.enroll.plist
change
<key>com.apple.ManagedClient.enroll</key>
<true/>
to
<key>com.apple.ManagedClient.enroll</key>
<false/>
So that the changes take effect
I upgraded from 14.6 to 15.0. Working fine.
If you have already run the commands previously in version 14.x, during the migration to 15.0 it was normal. You do not need to run it again.