If it's like all the others that've had this happen - and there were
LOTS back in the day, especially here in Oz where it gets hot.... Then:
- It IS on the inside.
- It IS from the heat radiated by the light globes.
- The light assembly IS glued together, but even if you can separate them & get them back together again, there's NO real way to fix the hazing that's IN the polycarbonate.
- The only real fix is replacement.
- The next thing to happen is often that the 'Chrome bits' under the polycarbonate start to change colour too, ending up as an uneven sorta 'burnt gold' :banghead:
There was a period waaay back in the day (maybe early 2014/2015?? :dontknow: ) when BRP allowed a 'Goodwill' replacement on them (some were charged for the labour?

) but I don't know if you stand any chance of getting that done now, altho you'll never know unless you ask - so I'd suggest you ask your dealer... dunno about your chances now tho?! :dontknow:
And just by the by, if you leave it too long &/or you ride slow enough in the sun on a hot day for long enough with your High Beams on, like I did for most of a the day at no more than 40kph on the
Very Hot 2014 Christmas Toy Run here in Oz, you can actually start to
melt the polycarbonate!! :yikes: (Do you
REALLY need to ask me how I know this happens?!

)
There are a few forum threads on this around if you search for them, probably mainly back before the end of 2015... Might be worth a bit of a look & spending some time reading... :dontknow: