I haven’t taken this course, but I was curious as to what you mean, so I checked out this lesson and the teacher ‘explains’ the cause of the flickering so:
‘If we play this animation, you’ll notice that the background flickers. This is because we are in orthographic view, which means we’re basically sampling one pixel per frame [WHAT!!!???] and it’s sampling random pixels from around this area, as we rotate.’
I do not know what this means, but adding a large enough ground plane does work to avoid the flickering, so, maybe your ground plane isn’t large enough????
Or maybe you could upload your .blend file to any cloud service (Dropbox, Google Drive,…..) and paste a link to that file here, so we could have a look…
