Pokemon Trade sparkles?

So me and my gf were trading just now (shiny charmander for shiny charmander) when I noticed something odd.
The screen around my shiny charmander sparkled and I thought "ah, that must be because of shinyness", but the charmander of my gf didnt have any sparkles. So I looked at her screen and on her screen it was the same: sparkles around my charmander but none around her own.
After trading my charmander (now hers) had above 80%. Did this have anything to do with the sparkles? We traded multiple other Pokemon afterwards, but none had sparkles (or over 80%) . Sadly I didnt make a screen of it, but it were very obvious and dominant white sparkles all over my tradeside.