Swift Swim bug on Kingdra.
I was playing OU Doubles in Showdown. I had a Mega Charizard Y with Drought.
The enemy appeared to have a Swift Swim Kingdra, and it was paired with Drizzle Politoed.
Kingdra was slower than me when Drought was on. Then, they activated Drizzle with a switch-in, and Kingdra was faster than me.
However, when I switched Charizard Y back in and had Drought on and killed Politoed, creating 5 turns of Drought, Kingdra continued to outspeed my whole team, as if Swift Swim was still active, and swept me.
I know I was faster than Kingdra, because I had a Salac Berry boosted Lucario with Max Speed IVs and EVs, as well as having a Jolly nature.
Kingdra without Swift Swim should not be able to outspeed that in any circumstance.