GAMEPLAY super slow auto attacks 6.16

I notice when i was playing a 3v3 bot game I as attacking a Malphite bot with frozen heart, and my attack speed became incredibly slow, slower then 15% less. I got a frozen heart, and it slowed enemies in the normal 15% fashion. and when i say i was slowed a lot, i mean like half speed or slower. Also, he had a small snowflake over his champion model (for frozen heart) and also a giant snowflake too.