Accident? No
There is already existing lines to make displays with this size and PPI? Why increase cost by making it slightly different? I'm sure they are working from the Apply Playbook as well, where they will 4X the amount of pixels / 2X resolution in a few generations.
FYI...this is why there are several models of the same screen size and resolutions. For example, Apple has a 27 inch and Dell has theirs.
The iPad screen was an Apple design, not a pre-existing part. Apple specified a customer design that suited exactly what they needed. HP is just picking up some surplus production now.
But every dimension of this tablet is an iPad clone, this was likely conscious decision to match them exactly across the board, maybe even to confuse some people.