OpenGL ES 2.0 or 3.0: Pow function issues

Question

OpenGL ES 3.0 on Android, when I use Pow(x) during preprocessing and Pow(1.0/x) during post-processing, image will display abnormally.

At first I thought there was a problem with the middle fragment shader, but later I removed all the middle fragment shaders and still showed exceptions. What is the reason for this?

Initial rendering process:

preprocessing -> other filters -> post-processing

Modified rendering process code,delete other filters and post-processing:

#version 300 es
precision highp float;
uniform sampler2D mTexture;
uniform float mPow;
in vec2 vTexCoord;
out vec4 vFragColor;
void main() {
    vec4 vFragColor1 = pow(texture(mTexture, vTexCoord), vec4(mPow));
    vFragColor = pow(vFragColor1, vec4(1.0/mPow));
}

pow range: 0.0-100.0