Command blocks and players cant assign particles to some entities like ThrownPotions type, although using /testfor commands detects these entities. I tried using the new UUID set/test, to see if I could set the particles to track the Potion not by its entity type but by its unique UUID but the parameters within the brackets were totally ignored:

e.g.:
/summon ThrownPotion ~ ~ ~ {UUIDLeast:1l,UUIDMost:1l,Potion:{id:373,Damage:16428,count:1}}

/particles portal ~ ~ ~ 0 0 0 0.1 10 @e[id=00000000-0000-0001-0000-000000000001]

... if this command is set in a command block it will assign the portal particle to ALL the entities in the world (loaded chunks)...

I didn't do further tests but my guess is that this bug could affect other other types of entities other than ThrownPotion ones.