OK - so I've unleashed my inner UAT Tester.
When I go to my own page, and preferences, if I uncheck "collapse signature" and "collapse "user information.....", then Save Changes, I return a message saying my changes have been saved, but the checks reappear in the boxes and no changes occur.
First time I did this, my screen also reverted to the Red colourway, but subsequent iterations, the Mild variant "stuck".
Obviously these aren't user critical, but you did ask.......
I'd best get on with the piece of work I'm trying to complete today, or I'll have to invoice you, rather than my client.