I went to print a long item, an 8”x3” box that was positioned along the Y axis (so going front to back). As it went to lay the skirt down it started to extrude andcfilament stickingvwith the bed coming forward. It made the back corners just fine and then as it hit about 2/3 coming back, the it wasn’t laying filament down. ( so if  was the footprint, the top part was fine the bottom wasn’t). I’m assuming it’s a slightly warped bed. Are there any manual adjustments for the Y axis? I know you can adjust the two rods on the left and right, not nothing front and back
What is the bed made of? glass beds are extremely flat so any warp you see will not be in that. Do you have a pei sheet that is lifting off the bed? did you level the bed with the corner adjustments? Are you sure the bed is actually warped and not just out of level?