Have this issue. Playing back a renedered clip where I have zoomed out - I have observed artefacts (pixelation) in all corneders. in the sky there comes some artefacts making the picture look bad.
When playing back raw AVHD file or playback clip insde Premiere Pro, there is no issues. So I guess it must be something with rendering?
The clips i AVCHD in 720 50P (PAL).
I have tried exporting/rendering in a lot of different formats - but with no luck.
Well - I understand why you don´t understand ;-)
I guess the issue is related to using the Red Giant Misfire Vignette. So might not be this forum I should ask this question. If anyone knows about this issue you are most welcome to help anyway. Sorry for any inconvinience.
I'm familiar with the plug-in. I just didn't understand the problem you were having.