Why does a 3D wing's CL keep increasing even after 50° AOA in XFLR5?
XFLR5 is not made for this kind of calculation. Do not trust the results.
Stall is not the end of lift. See below for 2D wind tunnel data collected by S. Hörner in his book Fluid Dynamic Lift. 3D results would look similar, but with a less steep gradient around 0° and lower peaks.




180° polar for several airfoils