[GAMEPLAY] Blitzcrank selfslow disables Wanderer mastery

[GAMEPLAY] Blitzcrank selfslow disables Wanderer mastery

When Blitzcrank uses his W he is slowed by it at the end of skill. Debuff from slow apparently counts as combat so he lose bonus movement speed from Wanderer mastery but he does not lose bonus speed from mobility boots (same as Wanderer it disables in combat). Steps to reproduce:

Play Blitzcrank and have wanderer mastery from utility tree (last one)   
Check normal speed number
Use W
Wait for slow to end
Check movement speed number. After end of slow it should be back to starting number but it is not.    
After aproximatelly 2s movement speed will jump to starting number.
Buy mobility boots.
Use W
Wait for slow 
Mobility boots are not disabled

I was alone in custom game and was in base so no combat. I tried it without wanderer mastery and problem did not appered. I used Riot Blitzcrank but that probably does not matter.

screenshot proof : http://i.imgur.com/2fAQgvY.jpg

As you can see after slow I am missing 16 speed for like 2 seconds.

Have a nice day.

edit: typos