It happens to me, too. I posted a bug report about it both here and at the developers site and it got added to a previous one. I think I saw something about it possibly having to do with Intel Embree not detecting older processors correctly and having to add custom checking. My Mac is an old 2011 Mac Pro tower with a relatively modern AMD card (Metal-compatible for future-proofing).
The crashes happen if, after switching to Cycles, I set the viewport to render preview or create a new Material.
Crashes for me all the time in Mojave. Crashes for any and all reasons: delete cube, add cube, add bevel, switch to wireframe view, select all, deselect all, switch workspace tab, change shader color, disable sun disk option in the new Nishita sky texture, reduce world strength. Changing metallic property of principled shader while in cycles render preview mode causes random portions of the object to disappear. Changing it again crashes Blender.