Lulu's Polymorph not working properly

Was in a match earlier today, and I was playing Lulu support. During the match, there were 4 instances that I can recall where I would use Whimsy on an enemy champion and they would continue to auto-attack or use spells while polymorphed. Each time this happened, it was when they would use a spell within 1 second of being polymorphed. The champions this happened to were a Shyvana and an Ezreal. The ezreal was able to use heal and his E while polymorphed, and the Shyvana was able to use her Ultimate, Flash, and Basic attacks. The one time she was able to basic attack was the same case where she Ulted while polymorphed. This instance made her change from a squirrel back to her ulted form, and she acted normally during the time she would've been polymorphed.