Apparently the blend node handles transparency properly, the original dirt texture had the same transparency issue. (I'll fix that later.) So added a make_tileable node to it, and made it export the texture.

game/modules/planets/test_planet/voxel_library/textures/dirt.tres

@@ -1,4 +1,4 @@
-[gd_resource type="Resource" load_steps=52 format=2]
+[gd_resource type="Resource" load_steps=56 format=2]
 
 [ext_resource path="res://addons/mat_maker_gd/nodes/mm_material.gd" type="Script" id=1]
 [ext_resource path="res://addons/mat_maker_gd/nodes/mm_node_universal_property.gd" type="Script" id=2]
@@ -8,6 +8,7 @@
 [ext_resource path="res://addons/mat_maker_gd/nodes/noise/fbm_noise.gd" type="Script" id=6]
 [ext_resource path="res://addons/mat_maker_gd/nodes/other/output_image.gd" type="Script" id=7]
 [ext_resource path="res://addons/mat_maker_gd/nodes/filter/blend.gd" type="Script" id=8]
+[ext_resource path="res://addons/mat_maker_gd/nodes/filter/make_tileable.gd" type="Script" id=9]
 
 [sub_resource type="Resource" id=1]
 script = ExtResource( 2 )
@@ -385,6 +386,15 @@ points = PoolRealArray( 0, 0, 0, 0, 0, 0.59322, 0, 0, 0, 0, 0.635593, 0.0823529,
 image = SubResource( 23 )
 input = SubResource( 43 )
 
+[sub_resource type="Resource" id=45]
+script = ExtResource( 2 )
+default_type = 5
+default_int = 0
+default_float = 0.0
+default_vector2 = Vector2( 0, 0 )
+default_vector3 = Vector3( 0, 0, 0 )
+default_color = Color( 0, 0, 0, 1 )
+
 [sub_resource type="Resource" id=44]
 script = ExtResource( 2 )
 default_type = 5
@@ -393,15 +403,32 @@ default_float = 0.0
 default_vector2 = Vector2( 0, 0 )
 default_vector3 = Vector3( 0, 0, 0 )
 default_color = Color( 0, 0, 0, 1 )
-input_property = SubResource( 19 )
+input_property = SubResource( 45 )
 
 [sub_resource type="Resource" id=38]
 script = ExtResource( 7 )
-graph_position = Vector2( 500, 400 )
+graph_position = Vector2( 700, 520 )
 image = SubResource( 44 )
-postfix = ""
+postfix = "_albedo"
+
+[sub_resource type="Resource" id=46]
+script = ExtResource( 2 )
+default_type = 4
+default_int = 0
+default_float = 0.0
+default_vector2 = Vector2( 0, 0 )
+default_vector3 = Vector3( 0, 0, 0 )
+default_color = Color( 0, 0, 0, 1 )
+input_property = SubResource( 19 )
+
+[sub_resource type="Resource" id=47]
+script = ExtResource( 9 )
+graph_position = Vector2( 480, 520 )
+image = SubResource( 45 )
+input = SubResource( 46 )
+width = 0.1
 
 [resource]
 script = ExtResource( 1 )
-image_size = Vector2( 128, 128 )
+image_size = Vector2( 256, 256 )
-nodes = [ SubResource( 2 ), SubResource( 4 ), SubResource( 7 ), SubResource( 9 ), SubResource( 11 ), SubResource( 13 ), SubResource( 18 ), SubResource( 26 ), SubResource( 28 ), SubResource( 33 ), SubResource( 34 ), SubResource( 35 ), SubResource( 36 ), SubResource( 38 ) ]
+nodes = [ SubResource( 2 ), SubResource( 4 ), SubResource( 7 ), SubResource( 9 ), SubResource( 11 ), SubResource( 13 ), SubResource( 18 ), SubResource( 26 ), SubResource( 28 ), SubResource( 33 ), SubResource( 34 ), SubResource( 35 ), SubResource( 36 ), SubResource( 38 ), SubResource( 47 ) ]