Why Does the Rendering Quality Decline in 3DGS Iterative Process with Unity Outputs?

[Songxinlei]

I used Unity to generate the camera intrinsic parameters in the "cameras.txt" file, the camera extrinsic parameters in the "images.txt" file, and the "points3D.txt" file based on point marking.
cameras.txt:
# CAMERA_ID, MODEL, WIDTH, HEIGHT, PARAMS[fx,fy,cx,cy] 1 PINHOLE 1920 1080 1758.385 1758.385 960 540 2 PINHOLE 1920 1080 1758.385 1758.385 960 540
images.txt:
`# IMAGE_ID, QW, QX, QY, QZ, TX, TY, TZ, CAMERA_ID, NAME
1 0.9238796 -0.3826834 0 0 -0.002161115 -2.06232 -2.064752 1 0.png

2 0.9237388 -0.3826252 -0.01612392 -0.006678747 0.06989768 -2.06232 -2.063494 2 1.png`

points3D.txt:
# IMAGE_ID, X,Y,Z,R,G,B 1 0.1727808 -0.576687 -0.2681421 162 10 11 2 0.1756815 -0.5763105 -0.2698661 59 0 0
The initial point cloud was generated normally.

However, during the rasterization rendering and iterative generation process in 3D Gaussian Splatting (3DGS), the rendering effect got worse as the number of iterations increased.
Iteration one:

iteration 3000:

Could you please tell me why this is happening? Thank you for your help.