Problem with RX Vega 56/64, freestyle rendering with transparent background

Hi

With the latest 2.80 build on Windows 10 and RX Vega 56 GPU I perfrom these steps:

Enable cycles.
Change device to GPU,
Go to film section, enable transparent,
enable freestyle.
Go to view layer tab, find the filter section, deselect all except freestyle.
Render image(F12)

This will render the freestyle edges of the default cube with transparent background. However for me Blender craches. Does anyone else have the same problem?

Here is my situation. I have two RX Vega 56, both Gigabyte but different models. One is from an early batch and the second is a Gaming OC edition. The only way I have got freestyle rendering with transparent background to work is with both cards physically in the box and with all monitors connected to one of the cards and rendering only on the card with no monitors connected. Then both cards can render independently if I just switch the cables.

If any of the cards are both rendering and pluged into a monitor, blender craches.

Can anyone confirm that they have the same problem, or even better, come up with a solution =)

I would really want to know if this is a driver issue, blender issue or an issue somewhere in my setup.

Thanks in advance