Steps to reproduce:

1) Download project "The Immortals.zip" and open in Unity.
2) Open scene "immortals_test" and press Play.
3) In Hierarchy window click on Claim >> LPManager >> PS0 >> ParticleVisualiser.
4) In Inspector window scroll down to the bottom and expand Shader.
5) Increase/decrease Soft Particles Factor value(look at image "Shader.png").
6) In Game window play game with (W,A,S,D and L.Shift) like 5 seconds, if it doesn't crash, change Soft Particles Factor value again and play it.

Note: Do 5th and 6th steps always in play mode until it crashes.
Usually takes 2-5 times to do those steps to crash Editor.

Reproduced with:
5.2.4f1, 5.3.5p1, 5.4.0b20.