glitch problem effect

[martins21140075]

Hello, I am a beginner of after effect, I decided to make an introduction following a tutorial. But I have a little problem.

To better understand here are the links of the tutorial in question: https://www.youtube.com/watch?v=3Rc0dNDzbuM&t=628s

at 10:38. Until there is no problem but when I add the effect FAST BOX BLUR and I click on REPEAT EDGE PIXEL, my effect disappears to leave trace to small white line, and impossible to solve this problem, I I am wondering that it was possible that my computer does not load the evolution but after relaunching the software nothing is done. You have any ideas ?

thank you in advance