Was it right after Magic Tour or right before Last live performance? There's some pics for evidence in 87 where he seems quite occupied and not the relaxed himself.. maybe it was due to the external changes in his body.. that made him more worried and less happy.
I'd say it'd changed by the Magic Tour. And that he knew something was wrong, even if his HIV tests had been negative up to that point.
Or maybe he just felt he was getting older in 1986.
if you listen to the freddie interviews cd from the box set, i noticed it, 86 at home in his garden interview he sounds down and at the 87 ibiza interviews where he talks about monserate* its obvious 86 onwards he deffo knew something,
i think hindsight makes it too easy to (mistakenly) read things into it, and incorrectly make assumptions
i think he's just a typical 40-year-old guy being typically reflective about himslef - see what you are like at 40? it'll be entirely different to the way you were at 20
let's be reasonable about it - he was clear in 86 but retested in 87 - when things were confirmed