It is not a fault code and can run normally, but it will automatically report an error during operation

As shown in the video, the program can run normally, achieving random visibility of three points, and there is no problem in the compilation process. The same statement above this statement does not report an error, that is, line 110 (gb[i].visible=true), but this statement (i.e. line 116, gb[i].visible=false) will have a strange error problem.

See the attachment for the corresponding code.

Edit: translated to English