Question Multiple Images When Alpha Blending Masking

Im trying to make shader for applying a mask to a texture. The mask is greyscale where black is transparent and white is viewable. Ive tried so many things, but this is the closest ive gotten. Why is it that whenever i try to set the alpha value to anything but 1 I keep seeing multiple instances of the image in the output texture along with other weird visuals?

Code (CSharp):

1. Shader "Unlit/MaskShader"
2. {
3.     Properties
4.     {
5.         _ForegroundTex ("Foreground", 2D) = "white" {}
6.         _MaskTex ("Mask", 2D) = "white" {}
7.     }
8.     SubShader
9.     {
10.         Tags { "RenderType"="Transparent" "Queue"="Transparent" }
11.         Blend SrcAlpha OneMinusSrcAlpha
12.         LOD 100
13.  
14.         Pass
15.         {
16.             CGPROGRAM
17.             #pragma vertex vert
18.             #pragma fragment frag
19.             #include "UnityCG.cginc"
20.  
21.             struct appdata
22.             {
23.                 float4 vertex : POSITION;
24.                 float2 uv : TEXCOORD0;
25.             };
26.  
27.             struct v2f
28.             {
29.                 float2 uv : TEXCOORD0;
30.                 float4 vertex : SV_POSITION;
31.             };
32.  
33.             sampler2D _ForegroundTex;
34.             sampler2D _MaskTex;
35.  
36.             v2f vert (appdata v)
37.             {
38.                 v2f o;
39.                 o.vertex = UnityObjectToClipPos(v.vertex);
40.                 o.uv = v.uv;
41.                 return o;
42.             }
43.  
44.             fixed4 frag (v2f i) : SV_Target
45.             {
46.                 // Sample the grayscale value from the mask texture
47.                 fixed4 maskColor = tex2D(_MaskTex, i.uv);
48.  
49.                 // Sample the color from the foreground texture
50.                 fixed4 color = tex2D(_ForegroundTex, i.uv);
51.  
52.                 // Blend the foreground color with the background color based on the mask alpha
53.                 // color = lerp(fixed4(0, 1, 0, 0), color, maskColor.r); // i see a lot of weird visuals
54.                 // color = lerp(fixed4(0, 1, 0, 0.5), color, maskColor.r); // i see like 5 instances with weird visuals
55.                 // color = lerp(fixed4(0, 1, 0, 0.99), color, maskColor.r); // i see the very beginnings of the second instance
56.                color = lerp(fixed4(0, 1, 0, 1), color, maskColor.r); // i see 1 instance and the background is green
57.  
58.                 return color;
59.             }
60.             ENDCG
61.         }
62.     }
63. }

 

Ive also tried this which i thought was the obvious answer:
color.a = maskColor.r; // i see like 5 instances with weird visuals
and this which i found online:
color.a *= maskColor.r; // very similar to the one above