Question about steaming

[kblue]

i gave my sister a scarf and she told me after she washed it she steamed ironed it (just steam not actual ironing) and she said the stretchyness went away (which is fine with her) and now its not bouncy springy streatchy yarn. Having steamed it she said it even got a little longer. She gave it another wash to see if it would go back to the way it was before she steamed it but it didn't. So out of curiosity why does that happen? Humm maybe i should've put a no ironing/steaming label on it

[Old Knitter]

Was the yarn a blend? Acrylic yarns don't seem to enjoy being blocked.