diff --git a/doc/contributions.txt b/doc/contributions.txt
index 6d8cef881b3083c695e1deb19bf8582f87278fb5..04dc5077831d02b85a0416369e179d80b06e17ad 100755
--- a/doc/contributions.txt
+++ b/doc/contributions.txt
@@ -282,6 +282,7 @@ Beq Janus
 	SL-11300
 	SL-15709
 	SL-16021
+	SL-18592
 Beth Walcher
 Bezilon Kasei
 Biancaluce Robbiani
diff --git a/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl b/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
index b26194f278823da1da30ec16972e52f09e3ee60c..1280bc20a8044444fff63461f67303ebb6127375 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/materialF.glsl
@@ -227,7 +227,7 @@ void main()
     vec4 diffcol = texture2D(diffuseMap, vary_texcoord0.xy);
 	diffcol.rgb *= vertex_color.rgb;
 
-#ifdef HAS_ALPHA_MASK
+#if HAS_ALPHA_MASK && (DIFFUSE_ALPHA_MODE != DIFFUSE_ALPHA_MODE_EMISSIVE)
 #if DIFFUSE_ALPHA_MODE == DIFFUSE_ALPHA_MODE_BLEND
     if (diffcol.a*vertex_color.a < minimum_alpha)
 #else