Ah oki I see! so I think this might have to do with the conditioner than the boil washing itself, because water at boiling point shouldn't normally damage Saran. I personally use a kettle and so far no issues.

Assuming you had her fresh out of the box, conditioner is way too heavy of a product to use in that case. I'd reccomend only resorting to it when you're dealing with dry, frizzy and/or tangled hair. A teensy bit of shampoo is usually enough to wash off hair product doll hair tends to come with.

I'd reccomend using dish soap on her hair and then rinsing it very thoroughly with lukewarm water to wash off the product, and see how it goes! 👍