{[{ShowParticles:0b}]} is ignored, summoned potions always use {[{ShowParticles:1b}]}

When attempting to summon a custom potion in 1.9 using the following command:
/summon ThrownPotion ~ ~1 ~ {Potion:{id:"minecraft:splash_potion",Count:1,tag:{CustomPotionEffects:[{Id:21,Amplifier:-5,Duration:199999980,ShowParticles:0b}]}}}, the ShowParticles tag doesn't work properly. No matter what value you use players splashed by the entity will always display particles.