This fixes a bug in refprobe blending, but I have no idea when I fixed it. It just started working all of sudden..

drivers/gles2/rasterizer_scene_gles2.cpp

@@ -944,6 +944,8 @@ void RasterizerSceneGLES2::_add_geometry_with_material(RasterizerStorageGLES2::G
 		int rpsize = e->instance->reflection_probe_instances.size();
 		if (rpsize > 0) {
 			bool first = true;
+			rpsize = MIN(rpsize, 2); //more than 2 per object are not supported, this keeps it stable
+
 			for (int i = 0; i < rpsize; i++) {
 				ReflectionProbeInstance *rpi = reflection_probe_instance_owner.getornull(e->instance->reflection_probe_instances[i]);
 				if (rpi->last_pass != render_pass) {
@@ -958,11 +960,11 @@ void RasterizerSceneGLES2::_add_geometry_with_material(RasterizerStorageGLES2::G
 				}
 			}
 
-			if (e->refprobe_0_index > e->refprobe_1_index) { //if both are valid, swap them to keep order as best as possible
-				uint16_t tmp = e->refprobe_0_index;
+			/*	if (e->refprobe_0_index > e->refprobe_1_index) { //if both are valid, swap them to keep order as best as possible
+				uint64_t tmp = e->refprobe_0_index;
 				e->refprobe_0_index = e->refprobe_1_index;
 				e->refprobe_1_index = tmp;
-			}
+			}*/
 		}
 
 		//add directional lights
@@ -1231,7 +1233,7 @@ void RasterizerSceneGLES2::_setup_geometry(RenderList::Element *p_element, Raste
 				}
 			}
 
-			//bool clear_skeleton_buffer = !storage->config.float_texture_supported;
+			bool clear_skeleton_buffer = !storage->config.float_texture_supported;
 
 			if (p_skeleton) {
 
@@ -1351,10 +1353,17 @@ void RasterizerSceneGLES2::_setup_geometry(RenderList::Element *p_element, Raste
 					glVertexAttribPointer(INSTANCE_BONE_BASE + 1, 4, GL_FLOAT, GL_FALSE, sizeof(float) * 12, (const void *)(sizeof(float) * 4 * 1));
 					glVertexAttribPointer(INSTANCE_BONE_BASE + 2, 4, GL_FLOAT, GL_FALSE, sizeof(float) * 12, (const void *)(sizeof(float) * 4 * 2));
 
-					//clear_skeleton_buffer = false;
+					clear_skeleton_buffer = false;
 				}
 			}
 
+			if (clear_skeleton_buffer) {
+
+				glDisableVertexAttribArray(INSTANCE_BONE_BASE + 0);
+				glDisableVertexAttribArray(INSTANCE_BONE_BASE + 1);
+				glDisableVertexAttribArray(INSTANCE_BONE_BASE + 2);
+			}
+
 		} break;
 
 		case VS::INSTANCE_MULTIMESH: {
@@ -1391,6 +1400,9 @@ void RasterizerSceneGLES2::_setup_geometry(RenderList::Element *p_element, Raste
 			glDisableVertexAttribArray(INSTANCE_ATTRIB_BASE + 2);
 			glDisableVertexAttribArray(INSTANCE_ATTRIB_BASE + 3);
 			glDisableVertexAttribArray(INSTANCE_ATTRIB_BASE + 4);
+			glDisableVertexAttribArray(INSTANCE_BONE_BASE + 0);
+			glDisableVertexAttribArray(INSTANCE_BONE_BASE + 1);
+			glDisableVertexAttribArray(INSTANCE_BONE_BASE + 2);
 
 		} break;
 
@@ -2110,9 +2122,11 @@ void RasterizerSceneGLES2::_render_render_list(RenderList::Element **p_elements,
 			}
 
 			if (!unshaded && !accum_pass && e->refprobe_0_index != RenderList::MAX_REFLECTION_PROBES) {
+				ERR_FAIL_INDEX(e->refprobe_0_index, reflection_probe_count);
 				refprobe_1 = reflection_probe_instances[e->refprobe_0_index];
 			}
 			if (!unshaded && !accum_pass && e->refprobe_1_index != RenderList::MAX_REFLECTION_PROBES) {
+				ERR_FAIL_INDEX(e->refprobe_1_index, reflection_probe_count);
 				refprobe_2 = reflection_probe_instances[e->refprobe_1_index];
 			}
 
@@ -2437,7 +2451,7 @@ void RasterizerSceneGLES2::render_scene(const Transform &p_cam_transform, const
 	if (p_reflection_probe_cull_count) {
 
 		reflection_probe_instances = (ReflectionProbeInstance **)alloca(sizeof(ReflectionProbeInstance *) * p_reflection_probe_cull_count);
-
+		reflection_probe_count = p_reflection_probe_cull_count;
 		for (int i = 0; i < p_reflection_probe_cull_count; i++) {
 			ReflectionProbeInstance *rpi = reflection_probe_instance_owner.getornull(p_reflection_probe_cull_result[i]);
 			ERR_CONTINUE(!rpi);
@@ -2448,6 +2462,7 @@ void RasterizerSceneGLES2::render_scene(const Transform &p_cam_transform, const
 
 	} else {
 		reflection_probe_instances = NULL;
+		reflection_probe_count = 0;
 	}
 
 	// render list stuff

drivers/gles2/rasterizer_scene_gles2.h

@@ -325,6 +325,7 @@ public:
 	mutable RID_Owner<ReflectionProbeInstance> reflection_probe_instance_owner;
 
 	ReflectionProbeInstance **reflection_probe_instances;
+	int reflection_probe_count;
 
 	virtual RID reflection_probe_instance_create(RID p_probe);
 	virtual void reflection_probe_instance_set_transform(RID p_instance, const Transform &p_transform);

drivers/gles2/shaders/scene.glsl

@@ -755,12 +755,12 @@ void reflection_process(samplerCube reflection_map,
 #endif
 
 	ambient_out.rgb = textureCubeLod(reflection_map, amb_normal, RADIANCE_MAX_LOD).rgb;
-	ambient_out.a = blend;
 	ambient_out.rgb = mix(ref_ambient.rgb, ambient_out.rgb, ref_ambient.a);
 	if (exterior) {
 		ambient_out.rgb = mix(ambient, ambient_out.rgb, blend);
 	}
 
+	ambient_out.a = blend;
 	ambient_out.rgb *= blend;
 	ambient_accum += ambient_out;
 
@@ -1357,12 +1357,14 @@ FRAGMENT_SHADER_CODE
 	ambient_light *= ambient_energy;
 
 	
+#if defined(USE_REFLECTION_PROBE1) || defined(USE_REFLECTION_PROBE2)
+
 	
-#ifdef USE_REFLECTION_PROBE1
 
 	vec4 ambient_accum = vec4(0.0);
 	vec4 reflection_accum = vec4(0.0);
 
+#ifdef USE_REFLECTION_PROBE1
 
 	reflection_process(reflection_probe1,
 #ifdef USE_VERTEX_LIGHTING
@@ -1379,6 +1381,9 @@ FRAGMENT_SHADER_CODE
 			   ambient_light, specular_light, reflection_accum, ambient_accum);
 
 
+
+#endif // USE_REFLECTION_PROBE1
+
 #ifdef USE_REFLECTION_PROBE2
 
 	reflection_process(reflection_probe2,
@@ -1407,7 +1412,7 @@ FRAGMENT_SHADER_CODE
 	}
 #endif
 
-#endif //use reflection probe 1
+#endif // defined(USE_REFLECTION_PROBE1) || defined(USE_REFLECTION_PROBE2)
 
 #ifdef USE_LIGHTMAP
 	//ambient light will come entirely from lightmap is lightmap is used