On my 21.5 in late 2014 iMac under macOS 10.14.5, everything is fine.
On my grandkid's recently purchased June 2017 MacBook Air (macOS 10.14.5), Godot kernel panics every single time as soon as I attempt to access the assets library. In the System Prefs, I downgraded the support from OpenGL 3 to 2, but the same thing happens. I haven't checked the console logs, but I will when I get my hands on that machine again.
IMNSHO, it is OK if an app crashes: it is the developer's sole responsibility. But crashing the system is an absolute NONO. Please, Godot, clean up your act.