Cauldron Gone due to Spell Levels Away

[Waltz5]

I was doing DoV on Samurai island with a Cauldron +3. I was doing it on my way and all of a sudden I find out it's on fire and has burned. I had no idea how it was lost.

Apparently someone casted Color Spray a good deal away from me yet somehow affected the cauldron causing it to burn (btw, how can cauldrons burn?) yet didn't effect me in any way.

I'd certainly hate to lose something as rare as a Cauldron +3 over a color spray casted where I couldn't even see it.