System Information
Operating system: Windows-10-10.0.16299 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 416.94

Blender Version
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: rBf6cb5f54494e
Worked: (optional)

Short description of error
In any viewport, when we have two or more GP objects overlapping and their origins have reverse stacking, a halo effect is seen.
Example: (overlapping: near to far)
Suzanne.001's strokes(nearest in the view), then Suzanne's strokes with its origin unchanged and then Suzanne.001 origin.

Exact steps for others to reproduce the error
In object Mode:
1_ Create a GP Suzanne.
2_ Duplicate it or create a new GP Suzanne(will named Suzanne.001).
3_ Move the second Suzanne(Suzane.001) in front to the other one(Suzanne).
4_ Move just the origin of Suzanne.001 to the back, behind the origin of Suzanne.
Then the halo will appear.