Collision bug

I have the tier 9 implant SR Mark 3, that the shield absorbs damage from collisions. The implant doesn’t say how much, but I have noticed on most of my ships, say ECM, Frigate, etc, collisions don’t do much dmg. On my ECM I can fly full speed almost and run into something and not take any hull dmg, just shield damage.

But On my fighter type ships, like the katana, a collision at not even 1/4 of my speed can take away up to 1/5th of my hull. 
I think this is a bug.

Katana is rank 7, This implant requires ship to be rank 9 to work. Basically implant requires ship of rank equal of higher to work.

Detailed description of implants is provided in the tutorial video here: