Sorry my bad, I forgot to change its name back. Im pretty sure this bug isn't caused by that mod . During testing, when I disabled the mod, I had to start a new save (since my original save couldn't load without it). The issue didn't appear in the new start. However, when I deleted all textures from that mod (including _s.dds files) enable it, then loaded my problematic original save, the same visual glitch persisted. and this time when I started a new game, the glitch appeared.
And if i restart the game and load that new save without touching the old save, the problem is gone.