LCD Text distorts underlying image. As result it looks if with different gamma.
It is simple to understad while looking into the shader :

    float3 dstClr = sample(dstColor, texCoord2).rgb;
    float3 dstAdj = pow(dstClr, invGamma);
    float3 result = mix(dstClr, srcClr, glyphClr);

dstAdj is NEVER used, but it must.