Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-11 13:50, hash: rB06312c6d2db8
Short description of error
In a perfect storm of GPU rendering + Hair with Radius Root size smaller or equal to the Tip size, bright white "cards" appear at the tips of some hair strands.
Switching to CPU rendering, the anomalies go away.
Also, making the Root size Large and the Tip size small reduces the cards, but they are still there.
Exact steps for others to reproduce the error
Open the attached file in Blender 2.80
Switch to the Camera view if not already there
Render (should be set to Cycles using GPU)
Switch to Cycles using CPU rendering
Select the hair object (eyebrows)
Go to the particle tab
Under Hair Shape, change the Radius Root to, say, 0.45 and the Tip to 0.1
Render using GPU - cards are still there but are much smaller.