In my scene I have 2 loader3D model (2 A-10 airplane) textured and 1 plane as ground also textured, 1 directional light which keep flying above and let shadow cast on all of them, 2 model also cast shadow on them selfs. at last, a hc camera added to let me pan around when I drag my mouse on the screen.

the problem is, after I add a cube textured skybox to my scene, I found when I pan the camera, skybox have a little chance to dissappear for some frame and then recovered. It’s very fast and randomly, cause it looks like blinking.

What I want to know is, is this problem cause by the new 4.1.1, or there’s some glitch in my code? I really appreciate if you can help me figure it out.

and… here’s my poor coding code: