It looks likes we’re affected by this bug:
https://bugs.openjdk.java.net/projects/JDK/issues/JDK-8211304?filter=allopenissues
In short, tab switching away from the editor while a dialog window is open (such as when opening a project) causes a crash.
One workaround that seems to work is to add Defold to the list under System Preferences > Security & Privacy > Accessibility. Please report if this doesn’t help in your case, or if you find an alternate workaround.
Obviously this is not an acceptable permanent solution. We’ll follow this issue in the coming weeks. If a patch gets merged we’ll likely update the jre shipped with Defold. Otherwise, we’ll have a closer look at openjdk.