version: 2.80 (sub 75), branch: master, commit date: 2019-07-23 10:51, hash: 19aa...
build date: 2019-07-23, 13:30:13
Inspect the attached .blend. Note that color transform has been set to Raw, so it's easier to see the gradients.
Set viewport draw type to Rendered.
View the two squares in both Eevee and Cycles.
The only difference between the shaders of the two squares is the type of curves node used. Both are set to linear extrapolation and ought to have the same output. in Eevee, however, the Vector Curves node does not work with values greater than 1.0. This bug only affects the Vector Curves node in Eevee, and only for positive values greater than 1.0.