Hey AlaNintendo!
I have noticed spikes in the editor when you turn on/off features on a material for the first time. I haven't experienced them at run time though - looking a the profiler it looks like its the editor compiling a new version of the shader when defines get enabled / disabled. Thats taking 1131ms for me which is a bit scary!
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I suspect I've either done something stupid or gone over the shader keyword limit or something.
Once the shader is compiled there should be no more spikes though (so shouldn't effect performance apart from in the editor)
Is your spike happening whilst playing? It strange it looks like its calling shader.editorloadvariant - the way I thought Unity worked was it makes a compiled version of your shader beforehand.... maybe i need to do something to make unity spit out variants properly when it builds:
https://blogs.unity3d.com/2014/05/06/shader-compilation-in-unity-4-5/