Size changes when exporting as PNG

Hello

I can see that this question has been asked before but what has been suggested doesn't seem to work. [:(]

I have an image that is 1920 x 1080 pixels.

Checking at the pixel level, the image lies perfectly within those bounds with nothing outside.

When trying to export as PNG, the size becomes 1943 x 1080.

What am I missing here?

It is slightly frustrating in that I then have to resize the PNG in MSPaint.

Any help would be HUGELY appreciated!

Thanks

Rich