When a material has a static bool parameter AND this is overridden in a material instance, Trying to change Blend Mode or Shading Model under the Material Property Overrides crashes the editor.

This doesn't happen without the static bool parameter in the parent or if the static bool is left alone and not overridden.

Regression: Checked 4.12 and 4.13 but couldn't repro

Here is the important log error:
Couldn't find Shader TShadowDepthVSVertexShadowDepth_OutputDepthfalse for Material Resource BaseMaterial!
With VF=FLocalVertexFactory, Platform=PCD3D_SM5
ShouldCache: Mat=1, VF=1, Shader=1
MaterialUsageDesc: LightingModel=MSM_DefaultLit, BlendMode=BLEND_Masked, SpecialEngine=0, TwoSided=0, TSNormal=1, Masked=1, Distorted=0, WritesEveryPixel=0, ModifiesMeshPosition=0, Usage={}

Steps to Reproduce

Attached a sample to make this easier.

1. In the attached project, open BaseMaterial_Inst
2. Override Blend Mode or Shading Model - note it works as expected
3. Check the override box for UseTexture (Static Bool Parameter)
4. Try step #2 again

Result: Editor crashes

Expected: Don't crash

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ComponentUE - Rendering
Affects Versions4.14.1
Target Fix4.15
Fix Commit3273971
Main Commit3389599
Release Commit3273971
CreatedDec 14, 2016
ResolvedJan 26, 2017
UpdatedJun 23, 2018