Giving creepers potion effects (haste, resistance, etc) with hidden particles and causing the creeper to explode will cause a certain radius around the creeper's death to emit black potion effect particles. This also applies to charged creepers. As usual, potion effects will be applied to the player if they walk into the particles. Duration and multipliers will be kept.

Steps to Reproduce:

/summon creeper

/effect give @e[type=creeper] resistance 100 1 true

Use Flint and Steel on the creeper so it explodes. 

Expected result:

no area effect cloud particles are shown

Actual result:

Effect particles are black.