Cait healed 3 time in less than 10 second

I was in a game with a Cait that healed 3 times in less than 10 second. I know he was not lifesteal cause there is green aura around her each time she healed. Also she did not build any lifesteal until I started pointing out about it. She kept arguing that the reason why she healed 3 times because she has heal (said notthing about mastery). But then against she healed 3 times in less than 10 seconds throughout the entire game