Sap Sipper not activated by non-damaging Grass Type Moves

[Roboteddy]

I noticed it in a Battle when some1 used leech seed on my Sap Sipper Goodra. First it only said "It's completely ineffective" (thats good tho :V) but nothing else. The Atk Moves of my Goodra werent dealing more Damage.

 

I made two Videos for that, testing it with Stun Spore.

 

Ignore the Music, I'm to lazy to remove it >.<

 

Bulpadia / Smogon says that every grass type move should affect sap sipper.

At least two grass type moves (stun spore and leech seed) are not affecting Sap Sipper.

 

 

(I made two more Videos but I've always been using Stun Spore only like a troll <.<

So I decided to make a new one with 3 moves (Stun Spore / Leech Seed / Giga Drain) )

 

Proof:

 

https://www.youtube.com/watch?v=XKTFYGt00Yk&feature=youtu.be

 

As you can see:

 

Leech Seed / Stun Spore + Sap Sipper "bugged"

Giga Drain + Sap Sipper works fine.