I am using version 18 of SSMS, though I have had this problem with earlier versions, too.
I always turn off Outline Statements with Intellisense. Which is fine until my next SSMS session, when Outlining appears again (though the setting remains off). To fix this, I need to set it on and off again.
Do others experience this?
(I do explicit outlining, using SSMS Boost & Regions.)