With a single eGPU (to avoid the nasty half hair bug with multiple GPUs) the Hair Rendering from RPR v2.0.32 produces a strange visual anomaly when compared to EEVEE and Cycles.
This file was setup entirely in 2.8 with RPR v2.0.32 and then adjusted to work in all three rendering engines.
Only one eGPU was used - an RX 580 on macOS 10.14.4 with the latest Nightly Blender 2.8 for macOS.
The Mac is a 2017 MBP 15 inch with a Radeon Pro 560 dGPU which was not used.
The external monitor was connected directly to the RX 580 and clamshell mode was enabled on the MBP.
There were no crashes while creating and testing this scene with one eGPU. I have not tested it with multiple GPUs yet. I may update the post when I next have two connected.
RPR final render:
EEVEE final render:
Cycles final render:
A sample blend file is attached for testing.