It could also be that your gantry has been torqued. I suggest checking the squareness of your table again. The simplest and most accurate method is to measure diagonal corners. It's far better than using a square. Once you have assurances that the table is square, run the gantry to the end and be check the distance between the ends of the table to the edge of the gantry.
While you're at it, check for the table sides being absolutely parallel by taking the covers off the gantry trolley (the wheels that run against the hardened steel runner on top of the sides) and be check that the trolly wheels on both sides sit in the V. As you move the gantry by hand (electrically disconnect the X motors first), it should be smooth, without binding and the trolly wheels should stay exactly centered.
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2013 PRS 96x60x12 (Centroid upgrade)
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12" indexer
Aspire
Rhino
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Ferrari 360
Prusa MK3S+
Prusa XL multi-tool