HS and stacking buffs.

So as most of you may or may not know, when stacking event + card + whatever event buff (Hunter's Luck, this DB buff) makes for 8x EXP. But using HS tends to negate the effect and have some monsters give you 0 EXP (such as Newts and Nest Golems, where Newts give 8x EXP while Nest Golems give 0).

Anyone know why this happens and to which monsters in particular? Is it just transforming monsters? Or is it something else?

Here's an explanation to the phenomenon that you experienced:

Nexon capped the amount of EXP gained at 8x (or below) the normal; anytime you go above the cap, the amount of EXP you gain will be negated. I believe this done to ensure that EXP gain cannot be abused/exploited.

These following EXP comboes will work:

1. 2x EXP card + 2x EXP event + Dual Blade 2x EXP (8x EXP total, NO HOLY SYMBOL)
or
2. 2x EXP card + 2x EXP event + Holy Symbol (6x EXP total)

Though, a notable exception is having a Welcome Back ring mule; it calculates EXP based on the "main" EXP you get, and therefore, doesn't get affected by this.

That probably happened because you had someone between level 105 and 109 in your party. You have to have a certain total level of leech-eligible characters in your party if you want 8x and HS to stack for your own kills. I think your level has to be 1/3 or 1/6 or something of the sum of the levels of everyone in the party, or somewhere in between. Welcome back rings aren't affected at all by this.

So let's say I went to fight Royal Guard S during 2x EXP with the buff and a card. HS will negate that effect? (Wishful thinking here, doubt I'd be able to actually find one by 2x. ._.)

So let's say I went to fight Royal Guard S during 2x EXP with the buff and a card. HS will negate that effect? (Wishful thinking here, doubt I'd be able to actually find one by 2x. ._.)

I would laugh so hard if you spent hours to kill Royal Guard S just to get 0 experience.

Just kidding. Don't try HS.