Grease Pencil Lights Glitch

Hi!

issue: Using Grease Pencil w/ lights results in this odd “cutoff” where the light is simply not displaying past a certain point on the GP plane. Video attached.

desired outcome: to have lights display fully over the GP object. At the moment, using lights gives me non-realistic results UNLESS the plane is facing the camera. Anything else creates this odd effect:

GP Settings: “use lights” on, render strokes in 3D space, all else default.