EPG problems

I have just purchased a VU+ DUO 4K se and I have a problem with the epg after setup all seamed fine until I pressed the epg button on remote epg displayed corectly but as soon as I changed channel or just exit epg the screen only shows a small picture at the top left and I can not find anyway to get full screen the only way is to do a full restart of the box then fullscreen returns apart from this all works great. I can change channels via ch up/down but the epg is driving me mad any help would be appreciated. I have tried all images vix atv pli they all have the same epg problem.

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