diff --git a/changelog.txt b/changelog.txt
index 7d3ea1e..2366060 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -1,6 +1,8 @@
 
 DD Mmm 17 - 1.49
 
+fix: broken rendering when the 2nd stage of a collapsed shader stage pair had non-white colors
+
 fix: shader stages using "wave" were not animated when the server time was too large
 
 add: con_scaleMode specifies the console text scaling mode
@@ -15,7 +17,7 @@ fix: the pukka3tourney2 slime wasn't green with r_vertexLight 1
 fix: the ct3ctf1 grate near quad was getting picmipped when it wasn't supposed to be
 
 fix: improved the player name look-up behavior for these commands: kick, banUser, dumpuser
-	if 2 players had the same name, it would just pick the first one (lowest client number)
+  if 2 players had the same name, it would just pick the first one (lowest client number)
 
 fix: multi-view mouse input sensitivity is now the same as in the UI for CPMA 1.50
 
diff --git a/code/renderer/tr_gl2.cpp b/code/renderer/tr_gl2.cpp
index 0da17ed..33f9159 100644
--- a/code/renderer/tr_gl2.cpp
+++ b/code/renderer/tr_gl2.cpp
@@ -185,7 +185,7 @@ static void GL2_DynLights_MultitextureStage( int stage )
 	GL_TexEnv( pStage->mtEnv );
 	R_BindAnimatedImage( &pStage->bundle );
 
-	stageVars_t svarsMT;
+	static stageVars_t svarsMT; // this is a huge struct
 	R_ComputeTexCoords( pStage, svarsMT );
 	qglEnableClientState( GL_TEXTURE_COORD_ARRAY );
 	qglTexCoordPointer( 2, GL_FLOAT, 0, svarsMT.texcoords );
diff --git a/code/renderer/tr_shader.cpp b/code/renderer/tr_shader.cpp
index 0f5f1bf..c08ce37 100644
--- a/code/renderer/tr_shader.cpp
+++ b/code/renderer/tr_shader.cpp
@@ -1697,7 +1697,6 @@ static void CollapseStages()
 	int numStages = shader.numStages;
 	shaderStage_t* aStages = &stages[0];
 
-#define CollapseSuccess { aStages[0].mtStages = 1; aStages += 2; numStages -= 2; continue; }
 #define CollapseFailure { ++aStages; --numStages; continue; }
 
 	while (numStages >= 2) {
@@ -1723,13 +1722,30 @@ static void CollapseStages()
 		if ( collapse[i].blendA == -1 )
 			CollapseFailure;
 
+		// Check that all colors are pure white on the second stage
+		// because the stage iterator can't currently specify
+		// another color array.
+		// Example shader broken without this extra test:
+		// "textures/sfx/diamond2cjumppad"
+		// The ring pulses in and out instead of only out.
+		static stageVars_t svarsMT;
+		R_ComputeColors( &aStages[1], svarsMT );
+		const int* colors = (const int*)svarsMT.colors;
+		const int colorCount = tess.numVertexes;
+		int allOnes = -1;
+		for ( int c = 0; c < colorCount; ++c )
+			allOnes &= colors[c];
+		if ( allOnes != -1 )
+			CollapseFailure;
+
 		aStages[0].stateBits &= ~GLS_BLEND_BITS;
 		aStages[0].stateBits |= collapse[i].multitextureBlend;
 		aStages[1].mtEnv = collapse[i].multitextureEnv;
-		CollapseSuccess;
+		aStages[0].mtStages = 1;
+		aStages += 2;
+		numStages -= 2;
 	}
 
-#undef CollapseSuccess
 #undef CollapseFailure
 }