As they have identical sub pixel layout they very likely come from the same factory.
I think one side of the mother glass has a few extra pixels that you can just not cut off and end up with the 80 pixels more on one direction?
If you start from a panel that cuts perfectly to 8K or 4K TV panels and you keep halving it won't go down evenly to 720p as it is not half of 1080p (1440p is half of 4K and 1080p is half of 1440p so they come out nicely without any wasted panel/pixels by cutting in half)
I think one side of the mother glass has a few extra pixels that you can just not cut off and end up with the 80 pixels more on one direction?
If you start from a panel that cuts perfectly to 8K or 4K TV panels and you keep halving it won't go down evenly to 720p as it is not half of 1080p (1440p is half of 4K and 1080p is half of 1440p so they come out nicely without any wasted panel/pixels by cutting in half)